Aluminum Research Articles

Surrogate-assisted optimization under uncertainty for design for remanufacturing considering material price volatility

Remanufacturing is a well-established end-of-life (EOL) strategy that promises significant savings in energy and carbon emissions. However, the current design practices are not remanufacturing-inclusive, i.e., the majority of products are designed for a single life cycle. As a result, potential products that can sustain multiple life cycles are deprived of additional benefits of being designed for remanufacturing, such as reduced material usage, lower cost, and improved environmental impact. Moreover, the uncertainty in design, material selection, and economics are not considered to produce remanufacturable designs. Accordingly, this research proposes a design for remanufacturing (DfRem) framework that accounts for design uncertainty and material price volatility. The framework systematically explores the design space, performs design optimization under uncertainty, followed by topology optimization to provide additional mass savings, and finally, a price volatility analysis for plausible design material choices. The candidate designs are evaluated based on their design mass, material price volatility, failure mode characteristics, carbon footprint, and embodied energy impacts. The proposed framework's utility is demonstrated via the use of an engine cylinder head case study subjected to thermo-mechanical loads along with fatigue and wear failure. Considering grey cast iron and aluminum alloy as the design material choices, it was found that the cast iron design reduced the initial design mass by 6% as opposed to a 5% decrease for aluminum. On the other hand, about 8% area of the cast iron design failed due to fatigue, compared to 3% for aluminum. We further observed that although the aluminum design provided better mechanical performance than the cast iron design, this material was more expensive and volatile in price.

Optical parameter inversion of thin films based on angular reflectance spectroscopy

This article proposes a method for obtaining the refractive index and thickness of thin films based on reflectivity at different angles combined with optimization algorithms. This method has high computational accuracy for both high absorption films (such as aluminum films, gold films, etc.) and low absorption films (such as MgF2 films). Since this study did not adopt the inversion scheme of refractive index dispersion equation fitting, it can be used for optical constant inversion in the case of unknown composition of coating materials. The results indicate that this method can simultaneously obtain high-precision information on the complex refractive index and film thickness of the coating material on the substrate. The calculation example achieved a thickness inversion error of 0.165% for a 2nm metal aluminum film layer and 0.3303% for a 150nm MgF2 transparent film layer. Therefore, this study may provide further guidance for high absorption and measurement of the complex refractive index and thickness of transparent films.

Recovery of Titanium from Red Mud Using Carbothermic Reduction and High Pressure Leaching of the Slag in an Autoclave

Red mud is a by-product of alumina production, which is largely stored in landfills that can endanger the environment. Red mud, or bauxite residue, is a mixture of inorganic compounds of iron, aluminum, sodium, titanium, calcium and silicon mostly, as well as a large number of rare earth elements in small quantities. Although certain methods of using red mud already exist, none of them have been widely implemented on a large scale. This paper proposes a combination of two methods for the utilization of red mud, first by carbothermic reduction and then, by leaching under high pressure in an autoclave in order to extract useful components from it with a focus on titanium. In the first part of the work, the red mud was reduced with carbon at 1600 °C in an electric arc furnace, with the aim of removing as much iron as possible using magnetic separation. After separation, the slag is leached in an autoclave at different parameters in order to obtain the highest possible yield of titanium, aiming for the formation of titanium oxysulfate and avoiding silica gel formation. A maximal leaching efficiency of titanium of 95% was reached at 150 °C using 5 mol/L sulfuric acid with 9 bar oxygen in 2 h. We found that high-pressure conditions enabled avoiding the formation of silica gel during leaching of the slag using 5 mol/L sulfuric acid, which is a big problem at atmospheric pressure. Previously silica gel formation was prevented using the dry digestion process with 12 mol/L sulfuric acid under atmospheric pressure.

Study of aluminum corrosion in contact with biogas before and after purification on different carbons

The study of aluminium corrosion in contact with biogas before and after purification on different types of carbon aims to understand the impact of impurities present in biogas, in particular hydrogen sulphide (H₂S), on aluminium degradation. The study highlights the importance of biogas purification in minimising aluminium corrosion. Depending on the level of purification and the types of carbon used for filtering, it is possible to improve the durability of infrastructures in contact with biogas. This has direct implications for the maintenance and operating costs of facilities using biogas as an energy source. Hydrogen sulfide (H₂S) is a colorless, flammable and highly toxic gas characterized by an unpleasant odor. It is often present in industrial and natural environments, particularly in biogas. This gas is involved in the degradation of metals used in anaerobic digestion equipment, in the petrochemical industry, etc. The aim of this work is to study the performance of biochar and activated carbon prepared from corn cobs in removing H2S from biogas, and to evaluate the reduction of the corrosive effect of filtered biogas on metallic aluminum. The impregnation and carbonization method was used to prepare activated carbon from corn cobs, and the gravimetric method to study the corrosion rate of metal in biogas. The results indicate that the activated carbon prepared is microporous, has a good specific surface and a better adsorption capacity. Furthermore, the prepared activated carbon samples also showed good H2S removal efficiency in the biogas. The aluminum-induced protective power values in filtered biogas for biochar and activated carbon are 58 % and 82.22 % respectively. We plan to increase the contact time and experiment with other metals and carbons.

Metallurgical Waste for Sustainable Agriculture: Converter Slag and Blast-Furnace Sludge Increase Oat Yield in Acidic Soils

The study is the first to examine the combined use of blast-furnace sludge as a source of microelements and converter slag as a soil-deoxidizing agent in oat (Avena sativa L.) cultivation in sod-podzolic soils. It has been established that blast-furnace sludge is a highly dispersed waste, which contains about 50% iron, 7% zinc, and a small amount of calcium, silicon, magnesium, aluminum, and sulfur. Hazardous components such as lead, arsenic, etc., are not detected. Converter slag comprises porous granules up to 3 mm in size, consisting mainly of calcium compounds (CaO, Ca(CO)3, CaSiO3, CaFe2O4) and a small amount of Mn, Al, and Mg trace elements. In a laboratory experiment, blast-furnace sludge increased the germination of oats by 5–10%, regardless of the addition of a deoxidizer (slag), but at the same time suppressed the growth of stem length by a maximum of 18% at 1 g∙kg−1. The addition of slag raised substrate pH and increased the index by 8% at a sludge concentration of 0.1 g∙kg−1. Root length in deoxidizer-free variants increased by 50–60% and with the addition of slag by 27–47%. Root dry mass also increased under the addition of sludge by 85–98%; however, the addition of slag reduced the indicator to the control level. In a field experiment with the combined application of waste, an increase in yield by more than 30% was shown. When soil was treated with slag and sludge, the height of plants increased by an average of 18%. It should be noted that the introduction of waste did not affect the quality of the grain. The use of slag increased the lead content in the soil, which is probably due to the sorption properties of calcium compounds in the slag, since lead was not found in the analyzed waste. Presumably, lead is sorbed by slag from the lower soil horizons, concentrating and immobilizing it in the upper layer. This version is supported by the absence of lead accumulation in straw and oat grain. The zinc-containing sludge increased the content of this element by 33% in the soil, as well as by 6% in straw and by 14% in grain. Thus, we found that the studied metallurgical wastes can be used as nutrients for agriculture, both individually and jointly. Overall, the proposed approach will contribute both to reducing the amount of accumulated waste and to improving the efficiency and sustainability of agricultural production and CO2 sequestration. However, the features of the accumulation of heavy metals in soil and plants under the influence of the analyzed types of waste require more in-depth study, including within the framework of long-term field experiments.

Theoretical and experimental analysis of the modulated phase grating X-ray interferometer.

X-ray grating interferometry allows for the simultaneous acquisition of attenuation, differential-phase contrast, and dark-field images, resulting from X-ray attenuation, refraction, and small-angle scattering, respectively. The modulated phase grating (MPG) interferometer is a recently developed grating interferometry system capable of generating a directly resolvable interference pattern using a relatively large period grating envelope function that is sampled at a pitch that is small enough that X-ray spatial coherence can be achieved by using a microfocus X-ray source or G0 grating. We present the theory of the MPG interferometry system for a 2-dimensional staggered grating, derived using Fourier optics, and we compare the theoretical predictions with experiments we have performed with a microfocus X-ray system at Pennington Biomedical Research Center, LSU. The theoretical and experimental fringe visibility is evaluated as a function of grating-to-detector distance. Additionally, quantitative experiments are performed with porous carbon and alumina compounds, and the mean normalized dark-field signal is compared with independent porosimetry measurements. Qualitative analysis of attenuation and dark-field images of a dried anchovy are shown.

Effect of Yttrium Addition on Microstructure and Mechanical Properties of Sr-Modified Low-Si Cast Aluminum Alloy

Effect of Yttrium Addition on Microstructure and Mechanical Properties of Sr-Modified Low-Si Cast Aluminum Alloy

A hybrid GRA-PCA-TOPSIS Technique Optimization of EDD Process Parameter on Drilling of AL8011/B4C/aloevera composites

A class of cutting-edge materials called hybrid aluminum metal matrix composites has been produced for applications such as the automobile, aerospace, and electronics industry and where weight and strengths are crucial factors. In the present research work, AA8011 composite reinforced with boron carbide particles and green aloevera has been fabricated using an economical stir casting process. In this 1% to 3% of boron carbide and 1% to 2% aloevera were used to fabricate the three different combinations of composites. The electrical discharge drilling process variables such as discharge current, pulse-on time, pulse-off time, and dielectric fluid pressure are investigated using the tubular copper electrode on drilling of hybrid composites. Performance aspects including drilling rate, roundness error, taper angle, and electrode wear rate have been analyzed, and the effect of process variables with the response surface methodology–central composite experimental design. The process parameters during the drilling of composites were optimized using a novel multi-criteria decision-making technique called the hybrid grey relational analysis–pulse component analysis–technique for order of preference by similarity to ideal solution method in order to maximize the drilling rate while concurrently minimizing other aspects. The optimum conditions were reached using the hybrid optimization method and a 1.5 mm tubular copper electrode with an input current of 9 Ampere , pulse on time 25 [Formula: see text]s, pulse off time 12 [Formula: see text]s, and pressure 60 kg/cm2. In comparison to the initial settings, the optimal condition shows a 25% faster drilling rate, with a 23% better roundness value, 14% lesser taper angle, and 7% lesser electrode wear rate.

Construction of Schottky barrier diode with a novel one-dimensional Cu(II)-based coordination polymer

Utilization of different kinds of materials in the fabrication of electronic device is considered as one of their most prominent employments. For modern civilization development of efficient electronic devices is extremely helpful not only due to their technological aspect but also for their laboratory to land applications. Keeping in mind of the above issues, a copper(II)-based zigzag one dimensional coordination polymer [Cu(4-dpds)(4-cba)2]n (where 4-dpds represents 1,2-di(pyridine-4-yl)disulfane and 4-cba represents 4-chloro benzoate anion) has been synthesized and well-characterized through X-ray single crystal diffraction analysis, powder X-ray diffraction analysis, thermogravimetric analysis, absorption spectral analysis and infra-red spectral analysis. Structural characterization through single crystal X-ray diffraction analysis reveals that the zigzag wave like architecture has been generated due to the presence of S-S linked ligands 4-dpds and strong hydrogen bonding interactions play pivotal role in the development of the supramolecular aggregate. Interestingly, the optical band-gap (2.15 eV) obtained from absorption spectra and the electrical conductivity at room temperature (measured as 9.73 × 10−4 S cm-1) revealed the semiconducting nature of the coordination polymer. The theoretical calculation projected HOMO-LUMO energy gap (2.11 eV) and the Fermi level (near to valence band) estimated from DOS also justified the p-type behavior of the derived material. The device fabricated by sandwiching the coordination polymer in between ITO coated glass substrate and metallic aluminum, was observed to exhibit non-linear rectifying nature in current-voltage characteristic plot. Therefore it is obvious that these kinds of easily synthesizable lower dimensional coordination polymers can be considered as potential candidates in application of Schottky like devices and also helpful for technological advancement as well as for the up-gradation of future research in the corresponding field.

Effect of Al/Cr ratio on structure, magnetism, and corrosion resistance of FeCoNiCr1-xAlx high entropy alloys

This study investigates the microstructure, magnetic properties, and corrosion resistance of FeCoNiCr1-xAlx (x=0, 0.25, 0.5, 0.75, 1) high-entropy alloys using the combination of experimental methods and first-principles calculations. XRD results reveal the FCC-BCC phase transition as x increases, and FeCoNiCr1-xAlx exhibits a noticeable dual-phase structure when x=0.75. The partial segregation between Ni and Al elements is indicated by SEM-EDS observations. The magnetism of both FCC and BCC phases become strong with increasing x, and the BCC phase consistently exhibiting higher magnetism than the FCC phase. Potentiodynamic polarization curves show that Al0.25 has the highest corrosion potential and the lowest corrosion current density. Under open circuit potential conditions, due to the difference between the corrosion potential and the open circuit potential, the electrochemical impedance spectroscopy measurements indicate that the corrosion resistance of the alloys follows the order: Al0 > Al0.5 > Al0.75 > Al0.25 > Al1. Considering both the soft magnetic behavior and corrosion resistance, Al0.75 is a optimal choice. These findings provide valuable insights for developing magnetic high-entropy alloy materials with superior corrosion resistance.

Commodity Market Downturn: Systemic Risk and Spillovers during Left Tail Events

We investigate systemic risk and spillovers in the commodity network during left-tail events using state-of-the-art methodologies: the Component Exponent Shortfall (CES), Quantile-Vector Autoregression (QVAR) and Causality-in-Risk. Our analysis focuses on five commodity groups: Energy (Crude Oil, Heating Oil, Natural Gas, Coal), Base Metals (Aluminum, Copper, Nickel, Zinc), Ferrous Metals (Iron, Steel), Precious Metals (Gold, Palladium, Platinum, Silver), and Others (Rubber). Across the models utilized, we consistently find that energy commodities and precious metals, along with copper as a standalone commodity, represent the most systemically risky group. Thus, portfolios incorporating these commodities are advised to implement more careful diversification to mitigate risks stemming from systemic factors. This may require additional attention to precious metals, as they are often considered safe-haven assets. Expediting the implementation of regulations that promote the replacement of fossil energy sources with green alternatives could be instrumental in managing systemic risk in the commodity market while also facilitating global sustainability. Finally, the results show that the impact of the Israeli-Palestinian conflict on both systemic risk and spillovers has been limited compared to the effects of COVID-19 and the Russia-Ukraine war.

Activated carbon encapsulated Aluminum metal–organic frameworks as an active and recyclable adsorbent for removal of different dyes and lead from aqueous solution

Activated carbon encapsulated Aluminum metal–organic frameworks as an active and recyclable adsorbent for removal of different dyes and lead from aqueous solution

Tribological Behavior of Hybrid Aluminum-TiB2 Metal Matrix Composites for Brake Rotor Applications

This research investigates the feasibility of hybrid aluminum metal matrix composites (MMC) incorporating TiB2 particles for brake rotor applications. The composites were produced by incorporating both in-situ, submicron-sized TiB2 particles and regular micron-sized TiB2 powders via stir and squeeze casting techniques into a A206 aluminum alloy matrix. Systematic adjustments in the fractions of in-situ and ex-situ TiB2 particles were conducted to evaluate their impact on wear behavior and mechanisms. Combination of both particle types allowed composites with up to 10 vol% of reinforcements. Composites with higher proportions of ex-situ particles demonstrated increased wear resistance compared to those solely composed of in-situ particles, control specimens without TiB2, and conventional cast iron counterparts. The lowest wear rate for the hybrid composites sliding against phenolic brake pads was 1.1 x 10-5 mm3/Nm, signifying a 3-fold reduction relative to cast iron sliding against the same pads. Wear analysis elucidated distinctive mechanisms within the hybrid composites, characterized by mild fragmented abrasive wear, adhesive wear, and plastic deformation, accompanied by the formation of an intermixed tribo-oxide layer.

Significant properties of AA7075-methanol nanofluid flow through diverging channel with porous material: Differential Transform Method

The recent industrial needs for the production process depending upon heat transfer properties of the fluids. However, the utility of the nanofluid in comparison to the conventional fluid is widely used because of its advanced coolant efficiency. In particular cooling of electronic devices, drug delivery systems, operation theatre, etc. the use of nanofluid shows its influential characteristics. As a result, the contemporary study aims to inspect the heat transmission effects of alloy nanoparticles via the base fluid methanol is presented through a diverging channel. Particularly, the aluminium alloy of AA7075 containing base metal Aluminium (Al) about 87.1-91.4%, Zinc (Zn) up to 5.1-6.1%, Magnesium (Mg) about 2.1-2.9%, Copper (Cu) within the range of 1.2-2.0%, Chromium (Cr) amounts 0.18-0.28%, Silicon (Si) usually less than 0.4%, Iron (Fe) less than 0.5%, Manganese (Mn) up to 0.3%, and Titanium (Ti) usually less than 0.2%. However, the flow through a permeable medium, the interaction of Darcy dissipation energies the flow phenomena. An appropriate similarity transform rule is employed for the transformation of the basic equations and solved analytically via the differential transform method (DTM). Further, a comparative analysis with previously establish outputs is presented to ensure the accuracy of the adopted methodology. The impact of characterizing factors on the flow profiles are presented graphically and the important outcomes are; the velocity profile shows its dual characteristic for the variation of alloy nanoparticles whereas the fluid temperature enhances significantly. Further, heat transport feature enhances for the augmentation in the Eckert number which is exhibited for the inclusion of dissipative heat.

Effects of Al variations on the microstructure and mechanical properties of laser-cladding AlxNbMo0.5Ti1.5Ta0.5Cr0.5 refractory high-entropy alloy coatings

Lightweight refractory high-entropy alloy coatings (RHEAcs) of AlXNbMo0.5Ti1.5Ta0.5Cr0.5 (where x = 0, 0.1, 0.2, and 0.3) were fabricated on 316L stainless steel surface by pre-placed powder laser cladding (LC) technology. The incorporation of Al element significantly enhanced the forming quality of coatings, resulting in nearly defect-free coatings with a thickness of 1.2-1.4mm. Microstructural analysis revealed that the coatings were primarily composed of body-centered cubic (BCC) solid solution and C15-Laves phase. Due to the influence of a single brittle BCC phase, the Al-free coating exhibited high strength and brittleness, leading to numerous defects caused by thermal stress. The introduction of Al element refined the microstructure and facilitated the formation of Laves phases at grain boundaries, thereby alleviating stress to a certain extent. Consequently, the microhardness of the RHEAcs was significantly higher than that of the substrate, with the Al-free coating achieving the highest microhardness of 1250 HV, which was 5.89 times that of the substrate. Wear resistance results indicated that, prior to annealing, RHEAcs with varying Al content outperformed 316L stainless steel. Post-annealing, the coatings exhibited significantly lower friction coefficients compared with the annealed 316L substrate. The Al-free coating showed significant accumulation of abrasive particles, leading to severe abrasive and oxidative wear. Conversely, post-annealing oxidation induced the formation of dense and directional oxide accumulation, resulting in a notable improvement in wear resistance. Finally, the underlying strengthening mechanisms have been proposed and analyzed.

Enhancing strength and ductility synergy through heterogeneous laminated structure design in high-entropy alloys

Heterogeneous laminated structure (HLS) design offers new opportunities to enhance the mechanical performance of high-entropy alloys (HEAs) through synergistic effects from heterogeneity. However, it remains challenging to introduce the HLS into HEAs via severe plastic deformation due to their strong work-hardening capacity. In this study, a specially designed multi-level HLS, characterized by alternatively stacked micro-grained soft CoCrFeNi layers and nanostructured ultra-hard Al0.3CoCrFeNi layers containing a three-phase microstructure (composed of nanograined face-centered cubic matrix, (Al, Ni)-rich B2 precipitates, and Cr-rich σ precipitates), is controllably introduced into FCC HEAs via a conventional thermo–mechanical processing involving hot-pressing, cold-rolling, and annealing. Meanwhile, thermo–mechanical processing induces Al element diffusion across the layer interface, resulting in the formation of an interfacial transition layer and the establishment of a strong interface bonding between the neighboring CoCrFeNi and Al0.3CoCrFeNi layers. As a result, the multi-level HLSed CoCrFeNi/Al0.3CoCrFeNi composite exhibits a yield strength as high as 1127±25.4 MPa while maintaining a large fracture elongation (up to (26.3±2.4)%). Such an excellent strength–ductility synergy surpasses that of most previously reported high-performance monolithic bulk CoCrFeNi and Al0.3CoCrFeNi HEAs prepared through careful chemical composition optimization and/or thermo–mechanical processing. Strong hetero-deformation induced strengthening benefited from the apparent microstructural/microhardness difference and the strong interface bonding between the neighbouring CoCrFeNi and Al0.3CoCrFeNi layers, together with simultaneous activation of multiple strain hardening mechanisms containing mechanical twinning, stacking faults and precipitation strengthening, is responsible for the excellent strength–ductility combination. This multi-level HLS and its fabrication strategy provide an enlightening way to develop strong and ductile HEAs and can also be applied to high-performance designs of other metallic materials.

EVALUATION OF PHYSICAL AND MECHANICAL PROPERTIES OF BN REINFORCED AL7079 METAL MATRIX COMPOSITES

Metal matrix composites (MMCs) are regarded as viable alternatives to conventional materials such as metals, plastics, and ceramics in structural applications due to their properties, including lightweight, high specific stiffness, elevated elastic modulus, enhanced specific strength, and excellent wear resistance. Among the many metal composites, aluminum metal matrix composites (MMCs) have emerged as sophisticated engineering materials for several prospective applications in engineering industries due to their superior qualities compared to typical aluminum alloys. Ceramic particles are the most extensively utilized reinforcements in MMCs due to their superior wear resistance, thermal stability, and exceptional bonding with the matrix. This research work has been conducted to develop ceramic particle-reinforced aluminum matrix composites and to evaluate their physical and mechanical properties. Al7079 alloy and Boron Nitride (BN) are selected as the matrix and reinforcement for the study respectively. The stir casting technique was utilized to fabricate the composites.Al7079-BN composites are prepared by varying the percentage of BN reinforcement particles from 0 to 8% by volume, with an increment of 2%. Test specimens were machined from the produced composites for the evaluation of microstructural, physical, mechanical properties according to ASTM standards. The microstructural analysis of the produced samples was conducted using scanning electron microscopy (SEM). The density of the composite was assessed empirically using Archimedes principle and theoretically through the rule of mixture. Microstructural analysis reveals a homogeneous distribution of BN particles throughout the matrix without any agglomeration, and it also demonstrates excellent bonding. The density of the composites decreased by approximately 4.6% with the incorporation of BN reinforcement up to 8%, attributed to the lower density of BN particles. The mechanical properties such as hardness, tensile strength, Youngs modulus, and compressive strength of the composite increases significantly.

Design a Gating System for an Aluminum Cast Three-Way Pipe in Sand Casting

The study of aluminum casting work with market demand in the metal casting industry, designing a gating system in aluminum casting using a three-way pipe-shaped sand mold workpiece as a basic shape template in metal casting, namely a flat-face core box with a core. The gating system has a metal inlet with design variables including the pouring height, pouring basin cross-sectional area, rest basin cross-sectional area, running system cross-sectional area and inlet cross-sectional area. From the studying and designing, actual casting experiments were conducted and simulation behavior was analyzed using Cast-Designer software to make decisions and find appropriate design approaches from analyzing simulation results including liquid metal filling time, molten metal flow behavior, metal solidification time and shrinkage porosity formation of the workpiece. The results of the casting experiment and behavior simulation were able to cast the pipe workpiece which is a flat-face core box mold. The analysis results from the software can be used for actual pouring, where the fully cast mold successfully produced a complete workpiece. This can be a guideline for future improvements to reduce the shrinkage of actual cast workpieces.

Mechanical Properties of Novel Hybrid Bamboo Fibre/Aluminium Mesh Reinforced Polymer Composite

Bamboo fibres are one of the sustainable lignocellulosic resources explored for polymer composites in recent years. Research has shown that bamboo fibres have the potential to be used in a variety of critical applications. Nevertheless, bamboo fibres are susceptible to thermal and hygroscopic loads, and their mechanical properties are limited by the unequal interfacial strength and varying fibre dimensions. Implementing hybrid procedures or incorporating alternative materials, such as aluminium metal, is strongly advised to address this issue. Thus, this study investigates the tensile and flexural performances of the hybrid bamboo fibre/aluminium expanded mesh-reinforced polymer composites. The composites were fabricated using epoxy resin reinforced with bamboo fibre, and an aluminium expanded mesh sheet was constructed using a vacuum infusion process utilising various stacking sequences and mesh sizes. The test findings indicated that the composite material exhibited tensile stress values ranging from 27 to 34 MPa and a corresponding tensile strain value between 1.1% and 1.6%. The flexural strength and strain values were measured within the range of 44 Mpa to 59 Mpa and 2.2% to 3.2%, respectively. ANOVA analysis showed that both stacking sequences and mesh size significantly affected the tensile performances of the composites, while only stacking sequences affected the flexural performance significantly. Overall, a hybrid composite of bamboo fibre and aluminium mesh is well-suited as a substitute material in industries requiring exceptional mechanical properties.

Substrate as the primer of relay-race spin-driven self-assembly of chiral molecules

The molecules of chiral N-trifluoroacetylated α-aminoalcohols can self-assemble and form long and thin fiber-like supramolecular structures (strings). The strings effectively grow on the surface of the substrate and the amount of them, as well as their morphology, depend on the properties of the substrate. In particular, self-assembly was not observed on the electroconductive substrates, such as some metals (copper and aluminum) and graphite. The strings were found on the surface of titanium due to the peculiarities of the titanium oxide’s properties. The strings usually emanate from some nucleation zones, where the growth was initiated and then proceeded spontaneously outside these areas. We supposed the relay-race scheme of the transfer of spin polarization, which describes the mechanics and thermodynamics of the observed self-assembly process. The scheme implies the preliminary orientation of two molecules, their mutual polarization accompanied by spin-polarization, and finally the binding of the molecules. We also suppose this mechanism can play a significant role in various self-assembly processes in living cells.