Low-energy Effects Research Articles

Superhydrophobic coating in cement mortar via inherent microstructure for enhanced efflorescence resistance

Efflorescence is commonly recognized as asignificant issue in cement-based exterior walls, which is caused by the presence of free water that is capable of dissolving soluble ions. The existing techniques for waterproofing suffer from problems related to inadequate adhesion and instability. This study introduce innovative superhydrophobic coating for cement mortar that enhances its efflorescence resistance. By utilizing the microstructure of cement mortar to create a layered roughness on the surface, the mortar surface was enriched with a pVA-siloxanehydrophobic emulsion, resulting in the formation of a three-dimensional network structure with Si-0-Si as the skeleton. So the superhydrophobic cement mortar is created by the dual effects of low surface energy and a rough texture. This unique structure achieves a contact angle of 150 ± 0.5°, creating a highly water-resistant surface. Durability tests confirm that the superhydrophobic properties are maintained under extreme conditions. XRD analysis and ion leaching tests show a significant reduction in Ca2⁺, Na⁺, and K⁺ concentrations compared to untreated samples, highlighting the coating's ability to prevent efflorescence. This method provides a promising solution for protecting cement-based exterior walls in construction.

EFFECT OF FEEDING LOW DIETARY ENERGY LEVELS ON GROWTH PERFORMANCE OF BROILER CHICKENS DURING THE FINISHER PERIOD

This study aimed at investigating the effect of low dietary energy on growth performance of broiler chickens at finisher stage. Two hundred and twenty five, four weeks old Amok broiler chicks were weighed and allotted to three dietary treatments containing 2 400 ME Kcal/Kg, 2 600 ME Kcal/Kg and 2 800 ME Kcal/Kg designated as A, B and C, respectively. Each treatment was replicated three times with twenty-five birds per replicate. Results showed that feed in take decreases as the energy value of the feed increases. There was statistical significance (P<0.05) in feed in take between birds fed diets A, B and C. The weight gain values of birds fed diets B and C were statistically similar which differs with birds fed diet A. There were no statistical differences between the treatments in terms of final live weight and feed conversion ratio. The study recommended that low energy diets should be formulated for poultry so as to minimize the accumulation of cholesterol in between the muscle fibres and on visceral organs which can consequently affects the physiological and metabolic functions of the birds, organoleptic characteristics, marketability of the products and health status of the consumer.

Optimization design of crashworthiness of polyurethane foam filled Origami thin wall square tube based on an surrogate model

Rigid polyurethane foam, due to its low density, light weight and effective energy absorption, can be used as a new filling material to improve the energy absorption capacity of pipe fittings, thus improving the overall crashworthiness of automobiles. In this paper, numerical simulations on rigid polyurethane foam-filled origami thin-walled pipe fittings are carried out. The effects of interlayer dihedral angle, number of layers of creased pipe, and filling of foam with different densities on the crashworthiness of the pipe fittings are compared and analyzed. Additionally, an surrogate model is established to predict the correlation between the above three factors and the model. Taking the specific absorption energy (SEA) and the initial peak force (PCF) as optimization objectives, the NSGA-II algorithm and the CHC algorithm were used for optimization analysis respectively. Simulation experiments were conducted to validate the accuracy of the optimized structural parameters. The results show that the CHC algorithm provides more accurate optimization results compared to the NSGA-II algorithm. The optimized optimal interlayer dihedral angle is 150°, the number of creased tube layers is 8, and the foam density is 0.3 g/cm3. Consequently, the tubing’s specific absorption energy is enhanced by 10.3 % compared to ordinary straight tubing, demonstrating the significant improvement in crashworthiness achieved through foam filling. This study proves that the filling of tubing with foam has excellent impact resistance, and the results provide a certain reference value for future research.

Low energy impact damage characteristics of epoxy coating on the surface of sandwich composites

AbstractWhen composite honeycomb sandwich structures are subjected to low energy impacts, the upper panel or the honeycomb core often suffers large damages, which are invisible, but affects the structural safety. To achieve non‐destructive detection of these damages, an epoxy resin film (ERF) was designed as a functional coating to display the internal failure features on structure surface. The effect of low energy impacts on the damage modes of the ERF was first investigated, and then the correspondence between the ERF damage characteristics and the structural internal failure was established. Simulation and experimental results showed that with the increase of impact energy, cracks on the ERF expanded from the radial radiation with a small extension range to the circumferential pattern with an increased damage area. Meanwhile, localized delamination appeared inside the upper panel, while the degree of flexure and crushing damage to the core continued to increase. Based on the analysis of the crack extension pattern of the ERF and the damage state of the upper panel and honeycomb core, a specific link between the ERF crack characteristics and the internal damages to the sandwich structure was obtained, which might offer a novel non‐destructive testing method for composite impact damages.Highlights Low energy impact damage in honeycomb sandwich structures was a concern. Impact damage response of epoxy resin film on sandwich composites was studied. Crack extension of the film showed a particular change from radial to annular. Specific link between film crack and sandwich structure damage was established. The results would be helpful for damage detection in sandwich composites.

Preparation of robust superhydrophobic surface on PET substrate using Box-Behnken design and facile sanding method with PTFE powder

Superhydrophobic surfaces have attracted increasing interests due to their excellent features, while achieving facile preparation of superhydrophobic surface with good mechanical stability is still a challenging work. In this paper, we prepared a superhydrophobic surface by sanding polytetrafluoroethylene powder directly onto the surface of a polyethylene terephthalate (PET) film by means of a simple sanding method with sandpaper. The fabrication parameters were firstly optimized using response surface methodology. Surface morphology and chemical composition of the fabricated surface were characterized by field emission scanning electron microscopy, Fourier transform infrared and x-ray photoelectron spectroscopy. The mechanical performance of the superhydrophobic PET surfaces was evaluated by tape peeling test, and potential applications of this surface in self-cleaning and anti-icing were finally carried out. The results showed that the water contact angle up to 153.5° and sliding angle less than ∼3° on PET surface could be prepared under the optimum conditions, and its superhydrophobicity of surfaces was attributed to the synergistically effect of low surface energy and surface roughness. The fabricated superhydrophobic surfaces also exhibited good resistance to abrasion, and they have great potential for application in the fields of self-cleaning and anti-icing.

Preparation and Performance of Fluorocarbon Polyurethane Amino Baking Paint for Graffiti-Resistant Whiteboards

Fluorocarbon polyurethane amino baking paint for graffiti-resistant whiteboards was designed and prepared. Firstly, perfluorohexylethyl alcohol (TEOH6) and hexamethylene diisocyanate (HDI) were reacted under certain conditions to obtain fluorocarbon mono-isocyanate, then fluorocarbon diols were obtained by reacting with trimethylolpropane, and finally fluorocarbon polyurethane hydroxy resin was formed by reacting with hexamethylene diisocyanate (HDI) and polyester diols. The synthesized hydroxyl resin was used as the basis to configure fluorocarbon polyurethane amino baking paint for graffiti-resistant whiteboards and was upgraded by adding hydroxyl silicone oil. Secondly, a series of performance tests, such as hardness, adhesion, flexibility, and corrosion resistance, were conducted to verify that the baking paint possessed excellent properties for use on writing whiteboards. The graffiti resistance of each paint film was evaluated by different methods, and it was found that the graffiti resistance was mainly due to the excellent hydrophobicity and oleophobicity of the paint films after the enrichment of fluorocarbon chains on their surfaces, and the combined effect of low surface energy caused by hydroxyl silicone oil crosslinked with amino resin. This study provides a theoretical basis and technical support for the preparation of fluorocarbon polyurethane baking paint for graffiti-resistant whiteboards.

Marine antifouling coating based on fluorescent-modified poly(ethylene-co-tetrafluoroethylene) resin

Abstract The growth of marine economy urgently needs non-toxic coatings. This study provides a novel and green coating that obtains outstanding antifouling performance by combining the low surface energy effect and the fluorescent effect. The coating was synthesized by reacting tetraphenylethylene (TPE) as the fluorescent component with poly(ethylene-co-tetrafluoroethylene) resin. The introduction of TPE provided the resin coating with lower surface energy and fluorescent properties, leading to improve the antifouling performance. This study indicates fluorescent TPE polymers for marine antifouling and opens new horizons for the exploitation of fluorescent antifouling coatings.

Enhanced adhesive and mechanically robust silicone-based coating with excellent marine anti-fouling and anti-corrosion performances.

Poly(dimethylsiloxane) (PDMS) is widely used in marine antifouling coatings due to its low surface energy property. However, certain drawbacks of PDMS coatings such as poor surface adhesion, weak mechanical properties, and inadequate static antifouling performance have hindered its practical applications. Herein, condensation polymerization is utilized to prepare PDMS-based polythiamine ester (PTUBAF) coatings that consist of PDMS, polytetrahydrofuran (PTMG), 2, 3, 5, 6-tetrafluoro-1, 4-benzenedimethanol (TBD) as the main chains and isobornyl acrylate(IBA) as the antifouling group. The surface adhesion to the substrate is enhanced due to the hydrogen bond between the coated carbamate group and the hydroxyl group on the surface of the substrate. Mechanical properties of PTUBAF are significantly improved due to the benzene ring and six-membered ring biphase hard structure. The strong synergistic effect of bactericidal groups and low surface energy surface endows the PTUBAF coating with outstanding antifouling performance. Due to the low surface energy surface, the PTUBAF coatings are also found to possess excellent anti-corrosion. Furthermore, since the PTUBAF coatings exhibit a visible light transmittance of 91 %, they can applied as protective films for smartphones. The proposed method has the potential to boost the production and practical applications of silicone-based coatings.

The universal one-loop effective action with gravity

We complete the so-called Universal One-Loop Effective Action (UOLEA) with effects of gravity and provide a systematic approach to incorporate higher dimensional operators in curved spacetime. The functional determinant stemming from the path integral is computed using the Covariant Derivative Expansion (CDE), in a momentum representation that does not rely on a specific choice of coordinate to be defined, as it often is. This efficient approach manifests an interesting novelty as it allows to integrate out chiral fermions in curved spacetime in a direct manner leading to new operators involving the curvature, and provides a new alternative to the use of Feynman diagrams in that regard. The method presented would very well fit in a code that performs CDE, offering the possibility to integrate out at one-loop fields on a curved spacetime background, including spin-2 fields, like the graviton. Eventually these results should provide an interesting way to study low energy effects of UV completions of gravity.

Highly Solvent Resistant Small-Molecule Hole-Transporting Materials for Efficient Perovskite Quantum Dot Light-Emitting Diodes.

Perovskite quantum dot light-emitting diodes (Pe-QLEDs) have been shown as promising candidates for next-generation displays and lightings due to their unique feature of wide color gamut and high color saturation. Hole-transporting materials (HTMs) play crucial roles in the device performance and stability of Pe-QLEDs. However, small-molecule HTMs have been less studied in Pe-QLEDs due to their poor solvent resistance and low hole mobility. In this work, three novel small-molecule HTMs employing benzimidazole as the center core, named X4, X5, and X6, were designed and synthesized for application in Pe-QLEDs. One of the tailored HTM-X6 exhibits excellent solvent resistant ability to the perovskite quantum dot (QD) inks due to its proper solubility and low surface energy. Our result clearly demonstrated that the synergistic effect of poor solubility and low surface energy facilitates the achievement of good solvent resistance to perovskite QD inks. As a result, a promising maximal external quantum efficiency (EQE) of 14.1% is achieved in X6-based CsPbBr3 Pe-QLEDs, which is much higher than that of X4 (9.16%) and X5 (6.60%)-based devices, which is comparable to the PTAA reference (EQE ∼ 15.8%) under the same conditions. To the best of our knowledge, this is the first example that a benzimidazole-based small-molecule HTM demonstrated a good application in Pe-QLEDs. Our work provides new guidance for the rational design of small-molecule HTMs with high solvent resistance for efficient Pe-QLEDs and other photoelectronic devices.

Decays of a bino-like particle in the low-mass regime

We study the phenomenology associated with a light bino-like neutralino with mass \lsim m_{\tau}≲mτ in the context of the R-parity violating Minimal Supersymmetric Standard Model. This is a well-motivated example of scenarios producing potentially light and long-lived exotic particles, which might be testable in far-detector experiments, such as the FASER experiment at the Large Hadron Collider. A quantitative assessment of the discovery potential or the extraction of limits run through a detailed understanding of the interactions of the light exotic fermion with Standard Model matter, in particular, the hadronic sector. Here, we propose a systematic analysis of the decays of such a particle and proceed to a model-independent derivation of the low-energy effects, so that this formalism may be transposed to other UV-completions or even stand as an independent effective field theory. We then stress the diversity of the possible phenomenology and more specifically discuss the features associated with the R-parity violating supersymmetric framework, for example neutron-antineutron oscillations.

Simulation studies of a full-ring, CZT SPECT system for whole-body imaging of 99m Tc and 177 Lu.

Single photon emission computed tomography (SPECT) is an imaging modality that has demonstrated its utility in a number of clinical indications. Despite this progress, a high sensitivity, high spatial resolution, multi-tracer SPECT with a large field of view suitable for whole-body imaging of a broad range of radiotracers for theranostics is not available. With the goal of filling this technological gap, we have designed a cadmium zinc telluride (CZT) full-ring SPECT scanner instrumented with a broad-energy tungsten collimator. The final purpose is to provide a multi-tracer solution for brain and whole-body imaging. Our static SPECT does not rely on the dual- and the triple-head rotational SPECT standard paradigm, enabling a larger effective area in each scan to increase the sensitivity. We provide a demonstration of the performance of our design using a realistic model of our detector with simulated body-sized phantoms filled with 99m Tc and 177 Lu. We create a realistic model of our detector by using a combination of a Geant4 Application for Tomographic Emission (GATE) Monte Carlo simulation and a finite element model for the CZT response, accounting for low-energy tail effects in CZT that affects the sensitivity and the scatter correction. We implement a modified dual-energy-window scatter correction adapted for CZT. Other corrections for attenuation, detector and collimator response, and detector gaps and edges are also included. The images are reconstructed using the maximum-likelihood expectation-maximization. Detector and reconstruction performance are characterized with point sources, Derenzo phantoms, and a body-sized National Electrical Manufacturers Association (NEMA) Image Quality (IQ) phantom for both 99m Tc and 177 Lu. Our SPECT design can resolve 7.9mm rods for 99m Tc (140keV) and 9.5mm for 177 Lu (208keV) in a hot-rod Derenzo phantom with a 3-min exposure and reach an image contrast of 78% for 99m Tc and 57% for 177 Lu using the NEMA IQ phantom with a 6-min exposure. Our modified scatter correction shows an improved contrast-recovery ratio compared to a standard correction. In this paper, we demonstrate the good performance of our design for whole-body imaging purposes. This adds to our previous demonstration of improved qualitative and quantitative 99m Tc imaging of brain perfusion and 123 I imaging of dopamine transport with respect to state-of-the-art NaI dual-head cameras. We show that our design provides similar IQ and contrast to the commercial full-ring SPECT VERITON for 99m Tc. Regarding 177 Lu imaging of the 208keV emissions, our design provides similar contrast to that of other state-of-the-art SPECTs with a significant reduction in exposure. The high sensitivity and extended energy range up to 250keV makes our SPECT design a promising alternative for clinical imaging and theranostics of emerging radionuclides.

Friedmann equations and cosmic bounce in a modified cosmological scenario

In this work we present a derivation of modified Raychaudhuri and Friedmann equations from a phenomenological model of quantum gravity based on the thermodynamics of spacetime. Starting from general gravitational equations of motion which encode low-energy quantum gravity effects, we found its particular solution for homogeneous and isotropic universes with standard matter content, obtaining a modified Raychaudhuri equation. Then, we imposed local energy conservation and used a perturbative treatment to derive a modified Friedmann equation. The modified evolution in the early universe we obtained suggests a replacement of the Big Bang singularity by a regular bounce. Lastly, we also briefly discuss the range of validity of the perturbative approach and its results.

Machine Learning for Optical Scanning Probe Nanoscopy.

The ability to perform nanometer-scale optical imaging and spectroscopy is key to deciphering the low-energy effects in quantum materials, as well as vibrational fingerprints in planetary and extraterrestrial particles, catalytic substances, and aqueous biological samples. These tasks can be accomplished by the scattering-type scanning near-field optical microscopy (s-SNOM) technique that has recently spread to many research fields and enabled notable discoveries. Herein, it is shown that the s-SNOM, together with scanning probe research in general, can benefit in many ways from artificial-intelligence (AI) and machine-learning (ML) algorithms. Augmented with AI- and ML-enhanced data acquisition and analysis, scanning probe optical nanoscopy is poised to become more efficient, accurate, and intelligent.

Effects of Low Mental Energy from Long Periods of Work on Brain-Computer Interfaces.

Brain-computer interfaces (BCIs) provide novel hands-free interaction strategies. However, the performance of BCIs is affected by the user’s mental energy to some extent. In this study, we aimed to analyze the combined effects of decreased mental energy and lack of sleep on BCI performance and how to reduce these effects. We defined the low-mental-energy (LME) condition as a combined condition of decreased mental energy and lack of sleep. We used a long period of work (>=18 h) to induce the LME condition, and then P300- and SSVEP-based BCI tasks were conducted in LME or normal conditions. Ten subjects were recruited in this study. Each subject participated in the LME- and normal-condition experiments within one week. For the P300-based BCI, we used two decoding algorithms: stepwise linear discriminant (SWLDA) and least square regression (LSR). For the SSVEP-based BCI, we used two decoding algorithms: canonical correlation analysis (CCA) and filter bank canonical correlation analysis (FBCCA). Accuracy and information transfer rate (ITR) were used as performance metrics. The experimental results showed that for the P300-based BCI, the average accuracy was reduced by approximately 35% (with a SWLDA classifier) and approximately 40% (with a LSR classifier); the average ITR was reduced by approximately 6 bits/min (with a SWLDA classifier) and approximately 7 bits/min (with an LSR classifier). For the SSVEP-based BCI, the average accuracy was reduced by approximately 40% (with a CCA classifier) and approximately 40% (with a FBCCA classifier); the average ITR was reduced by approximately 20 bits/min (with a CCA classifier) and approximately 19 bits/min (with a FBCCA classifier). Additionally, the amplitude and signal-to-noise ratio of the evoked electroencephalogram signals were lower in the LME condition, while the degree of fatigue and the task load of each subject were higher. Further experiments suggested that increasing stimulus size, flash duration, and flash number could improve BCI performance in LME conditions to some extent. Our experiments showed that the LME condition reduced BCI performance, the effects of LME on BCI did not rely on specific BCI types and specific decoding algorithms, and optimizing BCI parameters (e.g., stimulus size) can reduce these effects.

All-organic superhydrophobic coating with anti-corrosion, anti-icing capabilities and prospective marine atmospheric salt-deliquesce self-coalesce protective mechanism

Water-repellent and interfacial non-wetting superhydrophobicity has great potential to address corrosion/icing-induced material-deterioration problems. Herein, an all-organic superhydrophobic coating was constructed using facile and substrate-independent spray-coating method based on PTFE and PDMS. FE-SEM, EDS, and XPS techniques were used to analyze the surface topographies and chemical compositions. The coating exhibits superior anti-fouling and self-cleaning properties against various liquid and solid contaminants due to the synergic effect of low surface energy and hierarchical structures. The EIS and potentiodynamic polarization results show improved charge transfer resistance (Rct), positive shifted corrosion potential (Ecorr), and decreased corrosion current density (Icorr), implying significantly enhanced anti-corrosion performance with 99.83 % inhibition efficiency. Besides, the delay rate of ice-freezing time of the coating is 232 % at −5°C, 137 % at −10 °C and 204 % at −15 °C compared with uncoated Q235 substrate respectively. The ice adhesion strength of the coating accounts for only 6.55 % at −5°C, 7.03 % at −10 °C and 9.35 % at −15 °C than that of the bare Q235 carbon steel, demonstrating ultra-low ice adhesion force and anti-icing capabilities. The hygroscopic and deliquesce behaviors of NaCl salt particles reveal an intriguing salt-deliquescence self-coalescence phenomenon and prospective anti-corrosion mechanism for superhydrophobic materials in high-humidity marine atmospheric environments.

In-depth investigation of low-energy proton irradiation effect on the structural and photoresponse properties of ε-Ga2O3 thin films

Ga2O3 possesses an ultra-wide bandgap (∼4.9 eV) and an extremely large breakdown field strength (∼8 MV/cm), which promises extraordinary application potential in power electronics and ultraviolet optoelectronics. With the demand for highly durable devices in harsh environments such as in low earth orbit spacecraft, in-depth understanding of the particle radiation effect on the structural and performance degradation of the device is desired. In this work, we employ 150 keV low energy proton with intensity up to 5 × 1015 dose to irradiate the epitaxial ε-Ga2O3 thin films. The characterization of the structural and optical properties shows no detectable variations in lattice structure and optical transmission. In addition, with increasing irradiation dosage, a decrease of Ga3+ population and an increase of the concentration of oxygen vacancies are confirmed by X-ray photoemission spectroscopy. Photoresponse measurements further illustrate that, despite of a mild degradation in the photodetector performance, the device still shows a high photoresponsivity of 2.52 × 10-3 A/W and a large photo-to-dark current ratio over 103. Our work reveals that ε-Ga2O3 exhibits excellent radiation hardness under low-energy proton irradiation conditions and highlights the potential for operational optoelectronics in extreme environment.

Combined Effect of Microstructure, Surface Energy, and Adhesion Force on the Friction of PVA/Ferrite Spinel Nanocomposites.

Nanocomposite films based on spinel ferrite (Mg0.8Zn0.2Fe1.5Al0.5O4) in a PVA matrix were obtained. An increase in the spinel concentration to 10 wt.% caused an avalanche-like rise in roughness due to the formation of nanoparticle agglomerates. The lateral mode of atomic force microscopy (AFM) allowed us to trace the agglomeration dynamics. An unexpected result was that the composite with 6 wt.% of filler had a low friction coefficient in comparison with similar composites due to the successfully combined effects of low roughness and surface energy. The friction coefficient decreased to 0.07 when the friction coefficient of pure PVA was 0.72. A specially developed method for measuring nano-objects’ surface energy using AFM made it possible to explain the anomalous nature of the change in tribological characteristics.

Multifunctional Ti3C2Tx MXene-Based Composite Coatings with Superhydrophobic Anti-icing and Photothermal Deicing Properties.

Although advances in industrial products have brought convenience to our lives, severe weather has increased the safety risks to industrial facilities. Considerable efforts have been made to develop high-performance superhydrophobic anti-icing coatings. Nevertheless, designing a functional coating with both anti-icing properties and self-deicing remains a major challenge. Here, we propose a design strategy to exploit a photothermal superhydrophobic multifunctional coating with excellent anti-icing and deicing properties based on MXene by high-temperature sintering and layer-by-layer coating. Specifically, poly(tetrafluoroethylene) (PTFE) particles provide low surface energy and binding effects. Room-temperature-vulcanized silicone rubber (RTV) enhances the dispersion of the composite particles and the adhesion of the functional coating to a glass substrate. Furthermore, the functional coatings constructed with MXene exhibit outstanding photothermal effects, imparting excellent superhydrophobicity (CA = 160.18°, SA = 1.8°) and efficient photothermal conversion (equilibrium temperature of 109.3 °C). An anti-icing/deicing test is simulated to confirm their efficient anti-icing/deicing performance in practical applications. Overall, the functional coatings designed in this work can be applied in real industrial facilities.

Ag/Ce0.5Zr0.5O2 nanofibers: Visible light photocatalysts for degradation of p-nitrophenol

Ag deposited Ce0.5Zr0.5O2 nanofibers (CeZr-NF) were successfully synthesized by impregnation of Ag (0.5, 1.0, 1.5 and 2.0 wt.%) over CeZr-NF and thermal treatment at 500°C. The prepared Ag/CeZr-NF nanocomposites were analyzed by elemental analysis, XRD, Raman, FE-SEM, DR UV-vis, XPS and N2-adsorption measurements. The obtained results indicated that highly distributed Ag species were formed on the surface of CeZr-NF semiconductor because of strong interaction. The obtained Ag/CeZr-NF nanocomposites displayed excellent photocatalytic activity for degradation of p-nitrophenol (p-NP) activities under visible irradiation, compared to Ag metal, Ag oxides and CeZr-NF individually. The optimization of reaction parameters was performed by studying the influence of pH of solution, reaction time and catalyst amount on the p-NP degradation efficiency. The highest degradation efficiency of 96% was observed with acidic p-NP solution and catalyst mass of 0.2 g in 90 min for 1.5 wt.% Ag loaded CeZr-NF sample. Significant enhancement in degradation efficiency of the CeZr nanofibers after Ag deposition is because of the combination effects of low band gap energy, large pore size, high photocurrent density and slow e−-h+ recombination. After five recycles, the photocatalytic activity of Ag/CeZr-NF nanocomposites did not decline indicating the robust nature of synthesized composites.