Final Hybrid Research Articles

Dual-Mode Hybrid Quasi-SAW/BAW Resonators With High Effective Coupling Coefficient.

This article reports on a design journey for ScxAl1 - N-based dual-mode hybrid quasi-surface and bulk acoustic wave (quasi-SAW/BAW) resonators. Four types of acoustic excitation configurations are proposed in these designs based on Scx Al1-xN/6H-SiC stack architectures. The influence of Scx Al1-xN materials, film thickness, and device configurations on the performance is investigated. After design optimization, the final dual-mode hybrid quasi-SAW/BAW resonators comprise of top electrode, partially etched Scx Al1-xN pillars, and bottom electrode, which are stacked on a 6H-SiC substrate. The coupled quasi-SAW and BAW excited in the hybrid resonators enhance the resonance for both quasi-Rayleigh and quasi-Sezawa modes which results in a high effective coupling coefficient (Keff2) and phase velocity ( v ). Simulation results show that the optimized hybrid quasi-SAW/BAW resonator based on Mo/Sc0.4 Al0.6N/Mo/6H-SiC configuration with SiO2 filling the grooves has a remarkable Keff2 value of 14.55% and a high v above 7500 m/s, which make this kind of dual-mode hybrid quasi-SAW/BAW resonators have great potential in wideband and high-frequency applications.

Integrated self-healing coating system for outstanding corrosion protection of AA2024

This work reports the preparation of an integrated self-healing system that combines the anodization of Al-substrates with the deposition of environmentally friendly coatings prepared by sol-gel for obtaining an active corrosion protection of aluminum alloys AA2024. The system consists on a first step of forming appropriate anodized layers by controlling the potential and anodizing time. The second step is the infiltration of a cerium sol-gel sol and deposition of a Ce-glass like film, followed by a final hybrid silica sol-gel coating, creating an adherent, stable and active corrosion protective system. SEM, electrochemical techniques (potentiodynamic and EIS tests) as well as an accelerated corrosion test are used to analyze the structure of the coatings and to study the corrosion behavior of the different coatings on AA2024. The results of potentiodynamic measurements showed the excellent corrosion properties and EIS measurements confirmed the self-healing behavior by blocking the pitting defects. The outstanding self-healing corrosion protecting behavior provided by this integrated self-healing coating system offers an efficient chromium-free system for substituting chromium CCC and CCA coatings.

Optimal forecast combination based on ensemble empirical mode decomposition for agricultural commodity futures prices

AbstractImproving the prediction accuracy of agricultural product futures prices is important for investors, agricultural producers, and policymakers. This is to evade risks and enable government departments to formulate appropriate agricultural regulations and policies. This study employs the ensemble empirical mode decomposition (EEMD) technique to decompose six different categories of agricultural futures prices. Subsequently, three models—support vector machine (SVM), neural network (NN), and autoregressive integrated moving average (ARIMA)—are used to predict the decomposition components. The final hybrid model is then constructed by comparing the prediction performance of the decomposition components. The predicting performance of the combination model is then compared with the benchmark individual models: SVM, NN, and ARIMA. Our main interest in this study is on short‐term forecasting, and thus we only consider 1‐day and 3‐day forecast horizons. The results indicate that the prediction performance of the EEMD combined model is better than that of individual models, especially for the 3‐day forecasting horizon. The study also concluded that the machine learning methods outperform the statistical methods in forecasting high‐frequency volatile components. However, there is no obvious difference between individual models in predicting low‐frequency components.

Synthesis and incorporation of rod-like nano-hydroxyapatite into type I collagen matrix: A hybrid formulation for 3D printing of bone scaffolds

Over the recent years, nanometric hydroxyapatite (HA) has gained interest as constituent of hybrid systems for bone scaffold fabrication, due to its biomimicry and biocompatibility. In this study, rod-like nano-HA particles were introduced in a type I collagen matrix to create a composite mimicking the bone composition. HA nano-rods (40−60 nm × 20 nm) were synthesised by hydrothermal method involving the use of an ammonium-based dispersing agent (Darvan 821-A) and fully characterised. The homogeneous dispersion of HA nanoparticles throughout the final hybrid formulation was achieved through their suspension in a collagen solution in presence of Darvan 821-A. The resulting homogeneous collagen/nano-HA suspension proved to be suitable for extrusion printing applications, showing shear thinning and sol-gel transition upon simil-physiological conditions. Furthermore, mesh-like structures were printed in a gelatine-supporting bath by means of a commercial bioprinter further demonstrating the potential of the designed hybrid system for the fabrication of 3D bone-like scaffolds.

Multicompartmental Mesoporous Silica/Polymer Nanostructured Hybrids: Design Capabilities by Integrating Linear and Star-Shaped Block Copolymers.

Poly(2-vinyl pyridine)-b-poly(ethylene oxide) (P2VP-b-PEO) linear diblock copolymer and polystyrene–poly(ethylene oxide) (PS10PEO10) heteroarm star copolymer were used as building elements to prepare organic–inorganic hybrids. By using the layer-by-layer (LbL) methodology, these elements were integrated on mesoporous silica through non-covalent interactions, namely, ionic and H-bonding. For the latter, tannic acid (TA) was used as an intermediate layer. The deposition of the various layers was monitored by thermogravimetric analysis (TGA), electrophoretic measurements, and confocal microscopy. The final silica hybrid, bearing alternating P2VP-b-PEO and PS10PEO10 star layers was capable of carrying one hydrophilic and two hydrophobic chemical species in distinct compartments. These multicompartmental organic–inorganic hybrids could be used as nanostructured carriers for pH-responsive multiple drug delivery and potential theranostic applications.

Phase evolution in Zr-doped preceramic polymer derived SiZrOC hybrids

The present work focuses on the phase evolution of SiZrOC ceramic hybrids derived from the doping of Zr in a phenyl-containing silsesquioxane based preceramic polymer in the temperature range of 800 °C–1300 °C. A commercially available polymethylphenylsilsesquioxane polymer was doped with 5–20 mol% of Zr (through alkoxide source), and cross-linked. Inert atmosphere pyrolysis of thus produced powders yielded black colored SiZrOC ceramics. It was revealed that the dopants phase separate into t-ZrO2 beyond 800 °C. The crystallite size of t-ZrO2 was calculated from the X-ray diffractograms using Scherrer formula. Raman spectroscopy was employed to study the effect of dopant ion on retention of carbon and silica residual phases in the final ceramic hybrid. The crystallites of ZrO2 were further analyzed by high resolution transmission electron microscopy. The characterizations of Zr doped SiOxCy ceramic hybrids exhibit potential for coating systems in moderate to high temperature applications.

Analysis of a hybrid process for manufacturing sheet metal-polymer structures using a conceptual tool design and an analytical-numerical modelling

Abstract This paper presents an experimental and numerical study on the hybrid process of polymer injection forming (PIF) developed to manufacture sheet metal-polymer structures in one single operation. Despite the wide potential application of the PIF process, several challenges have prevented conducting an in-depth analysis of the simultaneous injection/forming condition that occurs during this hybrid process. One such challenge is the lack of a special feature in the regular injection molding machine for an independent application and control of the blank holder force (BHF) from the preset clamping force. To enable such, a new concept-to-design tool is proposed in this work. Using this specialized setup, the influence of the BHF, injection rate and their interactions are experimentally determined focusing on the transient PIF process variables and the quality of the final hybrid product. The use of the fluid-structure interaction (SFI) method to perform a multi-physics simulation on the PIF process incurs such computational costs that it is unreasonable to conduct multiple simulations to investigate the effects of several process parameters and their interactions. To achieve both efficiency and accuracy, a new combined analytical-numerical approach is presented to enable fundamental understanding of the PIF process physics considering the interaction of filling, stretching and drawing mechanisms. The feasibility of the proposed numerical and experimental methodologies is demonstrated through a comparative analysis of the deformation of the AA1100 sheet during the injection of a Polypropylene compound with different injection rates and BHF settings.

Design of a red-emitter hybrid material for bioimaging: europium complexes grafted on silica particles

A bottom-up approach was used to design a high luminescent biomarker composed of nanoparticles of silica grafted with Eu3+ complex, and the labeling of CHO-k1 ovary cells and gastrocnemius muscle cells was successfully observed in imaging tests. Spheroidal silica nanoparticles were prepared via the solgel method and then decorated with Eu3+ complexes in a sequence of reactions to form the final hybrid nanoparticles. The material was characterized by scanning electron microscopy (120 ± 19 nm), zeta potential (−15 mV), and photoluminescence (red emission with 32% quantum efficiency). The material exhibit high biocompatibility with CHO-k1 cells, as evidenced via the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method. CHO-k1 cells cultivated in the presence of the hybrid were investigated by microscopy techniques, and an active mechanism of internalization via phagocytosis was evidenced. Fluorescence and confocal images indicated red emission distributed in the cytoplasm, and especially around the nuclei. While for the muscle cells also stained with the luminescent particles, a distribution near the membrane was observed. Thus, the designed system proved to be safe and appropriate for use in bioimaging assays.

The efficiency of the use of “Biostrong 510” additive in the technology of broiler chicken meat production

Growing chickens for meat is the main link in the technological chain of broiler production. Broilers – the final hybrid obtained as a result of interbreeding of different chicken breeds lines (meat parent forms), tested for compatibility. Because of this, the bird has an intense growth rate, high taste of meat. Consumer demand for broiler meat has been increasing steadily in recent decades. Biostrong 510 (BIOSTRONG 510) herbal feed supplement to improve palatability and increase consumption or feed for farm poultry. The mechanism of action is based on the joint action of several plant substances, in which there are active substances, which, when combined, affect a certain category of animals. Four groups of broiler chickens (1 control and 3 experimental) of the Cobb 500 cross at the daily age of 50 heads each were formed to conduct the experiment by the method of analogues. The experiments were carried out with the daily up to 40 days of age. Expenses of feeds in the experimental groups was lower than in the control group by 0.07, 0.13, 0.12 kg, respectively. The purpose of this work was to establish the feasibility and effectiveness of enrichment of animal feed with vegetable feed additive "Biostrong 510" used in the production of meat broiler chickens. Assessing the results of scientific and economic experience, we can safely say that in all the experimental groups in which "Biostrong 510" was used as an additive, the gain in the live weight of broiler chickens was increased compared to the control group. In total, 4020 g of compound feed was spent for the period of an experiment for each experimental group of broiler chickens. Due to the improved taste of feed, the palatability in the experimental groups was higher than in the control group by 0.3 %; 0.9 %; 0.8 %. The cost of feed in the experimental groups was lower than in the control group. For example, in the control – 1, 87 kg per 1 kg of body weight gain. In experimental – below 0.07; 0.13; 0,12 kg, respectively. As a result of the experiment, it was found that the viability of experimental broiler chickens was almost 100%. The natural loss of livestock was only due to technological injuries. The obtained data on the productivity of broiler chickens indicate a favorable effect of plant feed additive on the live weight of broiler chickens. Based on the results of the research, we recommend to introduce a plant feed additive based on essential oils and plant substances "Biostrong 510" in the composition of complete feed in the amount of 150 g/t to increase live weight, growth intensity, preservation, meat productivity, reduce feed costs per unit of broiler chickens of the cross "Cobb 500".

Titanium based complexes with melanin precursors as a tool for directing melanogenic pathways

Abstract Bioinspired melanin based hybrid materials hold huge promise for developing multifunctional systems for a considerable set of applications. Yet, control of melanogenic pathway is a big challenge to allow rational design of nanostructured systems with tuned structures and improved properties. This study proves the ability of titanium ions interactions with melanin precursors in directing melanogenic pathway. To this purpose complementary spectroscopic evidences were collected to reveal that in the presence of a TiO2-sol, amino-acid complex of Ti(IV) ions and DOPA actually inhibits its cyclization, during oxidative process, thus leading to DOPA-based polyphenols, stable even in oxidative environment, rather than eumelanin. This hugely impacts on the biological properties of the final hybrid systems which, discloses relevant and durable antioxidant behavior but poor antimicrobial activity differently from DHICA-based hybrid nanostructures. Overall this study, discloses the high potential of ceramic templated approach in combination with the selection of melanin precursor in achieving a fine tuning of physico-chemical as well as bioactivity of melanin-TiO2 nanostructures, opening new scenarios towards the design of cutting-edge biomaterials with tailored biological properties.

Hybrid materials based on a layered zinc hydroxide solid and gallic acid: Structural characterization and evaluation of the controlled release behavior as a function of the gallic acid content

The formation of hybrid compounds from gallic acid immobilized into a layered zinc hydroxide is reported. Elemental analysis, X-Ray diffraction, X-ray thermo-diffraction analysis, FT-IR spectroscopy, scanning electron microscopy, and X-Ray photoelectron spectroscopy allowed to identify clear differences between the hybrid materials obtained depending on the gallate anion content within the inorganic matrix. The elemental analysis showed a reduction in the zinc content while a lower d-value was exhibited in the XRD pattern for the material with the highest gallate anion content. With these results was evidenced a structural transformation from a Zn5(OH)8(NO3)2·2H2O type phase to a layered Zn3(OH)4(NO3)2 type phase when the gallate anions entirely replaced the nitrate anions. The formation of the latter phase at room temperature has not previously been reported. The final hybrid compound with a formula of Zn3(OH)4(C7H6O5)2, shows an interlayer space of 7.7 Å in comparison to 7.0 Å for the Zn3(OH)4(NO3)2 phase, which suggests an arrangement of the organic molecule with a parallel orientation to the y-axis. The X-ray diffraction patterns as a function of temperature showed that a completed incorporation of the gallate anion into the material increased over a 200 °C range (from 150 to 350 °C), the temperature for the decomposition of the layered phase to ZnO. The organic-inorganic materials synthesized using gallic acid as a guest and a layered zinc hydroxide as a host matrix can act as controlled delivery and storage systems. The release of gallate anions was found to be concentration-dependent with a release mechanism described by the Elovich and Freundlich models.

Chemical versus physical grafting of photoluminescent amino-functional carbon dots onto transparent nematic nanocellulose gels and aerogels

Transparent matrices of low refractive index are promising carriers for photoluminescent nanoparticles targeting true volumetric 3D display applications. Complementation of transparency with a highly open-porous nanomorphology renders respective hybrid gels and aerogels additionally attractive for liquid and gas detection devices. Herein, we present virtually fully bio-based hybrids obtained by decorating highly transparent, nematically ordered gels and aerogels (15–20 mg cm−3) from carboxylated and individualized cellulose nanofibers (i-CNF) with amino-functional photoluminescent carbon dots (CD). The latter were obtained by microwave-assisted hydrothermolysis of lemon juice. As the way of anchoring the CDs onto the large internal surface of the porous i-CNF scaffolds (320 m2 g−1) has a great impact on the final properties of the hybrid materials including leaching of CDs and reusability of the hybrid, this study assessed the respective pros and cons of a physical and chemical bonding approach. The results confirmed the superiority of covalent grafting. Aqueous carbodiimide coupling of amino-functionalized CDs afforded higher yields of CDs in the final hybrid aerogels, distinctly higher specific surface values (491 m2 g−1) and slightly enhanced mechanical properties while the high light transmittance and nanomorphology of the i-CNF precursor alcogels is virtually not compromised. Therefore, we conclude that the luminescent i-CNF/CD-chem hybrid materials of this study are promising candidates for environmentally friendly chemical sensing and volumetric display applications.Graphic abstract

Weighted sequential hybrid approaches for time series forecasting

Over the past few decades, a large literature has evolved through time series forecasting via combining different individual models by employing various hybrid strategies in order to improve forecasting accuracy. One of the most attractive and extensively-used methodologies, proposed in the literature of time series forecasting is the series methodology in which different components in data are sequentially modeled. In this hybrid methodology, a time series is decomposed to dissimilar components and then appropriate models for each component is used sequentially in order to capture all kind of patterns in data. It means that the output of the first model is used as input of the second model, and the output of the second model is used as input the third model, and so on. Recent literature confirms that the sequential hybrid methodology has become commonplace approach for combining different models and can yield desired accuracy. However, this methodology, despite of all advantages, has some critical assumptions that may degenerate its performance in some specific situations. One of the most essential of these assumptions is that the equal weights are considered for individual components. In other words, the related importance of each component rather than other those components are not considered in calculating procedure of the final hybrid forecasts. In this paper, a novel weighted sequential hybrid model is proposed in order to lift the equal weight assumption in the traditional series hybrid models. In the proposed model, components are first modeled sequentially and then the optimal weight of each component is calculated based on a least square process. It can be theoretically demonstrated that the performance of the proposed model, due to lift the equal weight constraint, will not be worse than traditional sequential hybrid models by same components. Empirical results of four well-known real word benchmark data sets also indicate the effectiveness and appropriateness of the proposed model in comparison to traditional bi-component series hybrid models.

Morphology on Reaction Mechanism Dependency for Twin Polymerization.

An in-depth knowledge of the structure formation process and the resulting dependency of the morphology on the reaction mechanism is a key requirement in order to design application-oriented materials. For twin polymerization, the basic idea of the reaction process is established, and important structural properties of the final nanoporous hybrid materials are known. However, the effects of changing the reaction mechanism parameters on the final morphology is still an open issue. In this work, the dependence of the morphology on the reaction mechanism is investigated based on a previously introduced lattice-based Monte Carlo method, the reactive bond fluctuation model. We analyze the effects of the model parameters, such as movability, attraction, or reaction probabilities on structural properties, like the specific surface area, the radial distribution function, the local porosity distribution, or the total fraction of percolating elements. From these examinations, we can identify key factors to adapt structural properties to fulfill desired requirements for possible applications. Hereby, we point out which implications theses parameter changes have on the underlying chemical structure.

Degree of cure, mechanical properties, and morphology of carbon fiber/epoxy- PP hybrids manufactured by a novel single shot method

The authors detail the creation of a hybrid multi-material structure via the injection of polypropylene (PP) with high ductility into a robust CF/Epoxy thermoset sheet. The purpose of this hybrid method involves combining the inherent properties of both thermoset and thermoplastic materials in a new hybrid structure while reducing the cycle time and tooling system. Specifically, the effect of pre-heating time, injection temperature, and injection speed rate on the deformation of the prepreg and polymer penetration through prepreg sheets were evaluated. The results of the experimental design indicated that the hybrid structures were manufactured with no penetration present in any combinations of parameters. An inadequate deformation characterized the samples created at a lower injection temperature, and pre-heating time, with insufficient adhesion as a result. High injection speed resulted in enhancing the formability and joinability. Also, the effect of the mentioned process parameters on the curing of prepreg sheet and bending behavior of final hybrid component were investigated through Differential Scanning Calorimetry (DSC), and the Three-point flexural test, respectively. Both DSC and Three-point test results illustrated the increase in pre-heating time, and the injection temperature enhanced the amount of curing and an increase of stiffness on the hybrid component.

Design of Wind and PV-Solar Hybrid System for Tem Equipment in Geophysical Exploration for Geothermal Energy

The research was tailored to optimize the design of a hybrid system that is powered by wind and solar energy in sustaining the power requirements of the Transient Electromagnetic Method (TEM) instrumentation. The issue addressed by the research was the unsustainability aspect of the batteries during TEM data collection. Therefore, the research tried to come up with an alternative that involved making power from wind and solar resources to power the TEM equipment. The research design began by doing a quantification analysis of both wind and solar resources in the geothermal area. In addition, a terrain and security analysis was done. Lastly, a hybrid system was designed considering its component specification that was governed by the wind and solar characteristics of the geothermal area under study. The sole aim was to solve issues faced with one form of green energy, geothermal energy, with other forms of green energy, wind and solar energy. The end result was the design of a revised final hybrid system that was able to sustain the power requirements of the TEM equipment during data collection in a geophysical survey with the available natural wind and solar resources in the Olkaria Geothermal field. From the analysis, it was evident that design of the hybrid system will primarily depend on the availability of the wind and solar resources in the area under study and the power requirements of the application being powered by the hybrid system.

Fermi level shift in carbon nanotubes by dye confinement

Dye confinement into carbon nanotube significantly affects the electronic charge density distribution of the final hybrid system. Using the electron-phonon coupling sensitivity of the Raman G-band, we quantify experimentally how charge transfer from thiophene oligomers to single walled carbon nanotube is modulated by the diameter of the nano-container and its metallic or semiconducting character. This charge transfer is shown to restore the electron-phonon coupling into defected metallic nanotubes. For sub-nanometer diameter tube, an electron transfer optically activated is observed when the excitation energy matches the HOMO-LUMO transition of the confined oligothiophene. This electron doping accounts for an important enhancement of the photoluminescence intensity up to a factor of nearly six for optimal confinement configuration. This electron transfer shifts the Fermi level, acting on the photoluminescence efficiency. Therefore, thiophene oligomer encapsulation allows modulating the electronic structure and then the optical properties of the hybrid system.

Structure, mechanical and thermal properties of polypropylene based hybrid composites with banana fiber and fly ash

Polypropylene (PP)-Flyash (FA) composites containing natural banana fiber (NF) treated by Maleic anhydride and NaOH are reported here. Mechanical properties such asflexural modulus and impact strength were improved considerably which were maximum for 20% fly ash filled PP-NF treated composites. There is extensive nucleation of theα crystalline phase of PP in presence of the additives. This changed to mixed α phase with slight β content in presence of FA and treated NF as confirmed by XRD and DSC. The results on the mechanical properties have been explained on the basis of structure development of PP in presence of fly ash and treated NF. The results have also been analyzed with the help of different models for filled polymer composites and using rule of mixtures of two composites to form final ternary hybrid composite. Some agreement is found if a factor is introduced for redistribution of fibers due to added FA as third component. However, the synergistic behavior at certain composition can be explained on the basis of crystalline structure and nucleation due to the additives.

A Hybrid Knowledge Push Method Based on Trust-Aware and Item-Cluster Oriented to Product Design

A knowledge push system as a proactive method of knowledge management, and is an effective way to push knowledge to designers in the product design process. Knowledge push can help to improve design efficiency and quality, but the knowledge pushed to designers is less applicable in engineering scenarios. To improve the quality of knowledge push, we propose the trust-aware and item-cluster strategies to extract the two nearest neighbors of the designers and the design knowledge. Next, we adapt a fusion model for the two nearest neighbors, which is solved based on the gradient descent algorithm. Finally, the rating prediction that the designer gives to the knowledge component is the decision point of the knowledge push system, where we propose our final hybrid knowledge push method. A knowledge push system of CNC machine tools design is used to confirm that our method outperforms the other widely adopted methods.

Decorated silica particles with terbium complexes as luminescent biomarker for cell imaging

Most commercially available fluorescent dyes used for cellular images are toxic and their luminescence is often outshined by the intrinsic autofluorescence of the biological medium, the use of long emission lifetime inherent of the lanthanide compounds is a viable alternative. This paper reports the development of a luminescent hybrid based on silica nanoparticles decorated with Tb3+ complexes suitable for use in exploratory tests as biomarkers in the visualization of CHO-k1 cells by microscopy techniques. To achieve this aim, spherical/spheroidal (∼125 nm) functionalized silica particles were prepared by the sol-gel method and had their surface functionalized covalently with Schiff base ligands. Tb3+ Complexes were bonded onto the particles surface by a step-by-step methodology approach. By zeta potential, it was possible to investigate the particles surface charge after each synthesis step, reaching a negative value for the final hybrid, which showed intense luminescence in the green region, where the Tb3+5D4 → 7FJ transitions were observed in the emission spectrum. After the benzoic acid ligand (BzAc) addition, there was an intensification of Tb3+ emission, as well as an increase in the emission lifetime. Concerning the biological application of the material, the CHO-k1 cell viability was evaluated by the MTT method in the presence of the SiO2-[Tb(SB)(BzAc)y] hybrid, and high biocompatibility was observed. The absorption process of particles by the cells was investigated by TEM, suggesting an endocytosis mechanism as a probable uptake process. The confocal images indicated a green emission of the biomarker due to the Tb3+, distributed through the cytoplasm, mainly closely to the cell nuclei. Therefore, the silica particles decorated with Tb3+ complexes proved to be suitable to act as biomarkers in biological assays and cellular imaging.