Acoustical properties of a 3D printed honeycomb structure filled with nanofillers:Experimental analysis and optimization for emerging applications

The novelty of this research lies in the successful fabrication of a 3D-printed honeycomb structure filled with nanofillers for acoustic properties,utilizing an impedance tube setup in accordance with ASTM standard E 1050-12.The Creality Ender-3,a 3D printer,was used for printing the honeycomb structures,and polylactic acid(PLA)material was employed for their construction.The organic,inorganic,and polymeric compounds within the composites were identified using fourier transformation infrared(FTIR)spectroscopy.The structure and homogeneity of the samples were examined using a field emission scanning electron microscope(FESEM).To determine the sound absorption coefficient of the 3D printed honeycomb structure,numerous samples were systematically developed using central composite design(CCD)and analysed using response surface methodology(RSM).The RSM mathematical model was established to predict the optimum values of each factor and noise reduction coefficient(NRC).The optimum values for an NRC of 0.377 were found to be 1.116 wt% carbon black,1.025 wt% aluminium powder,and 3.151 mm distance between parallel edges.Overall,the results demonstrate that a 3Dprinted honeycomb structure filled with nanofillers is an excellent material that can be utilized in various fields,including defence and aviation,where lightweight and acoustic properties are of great importance.

Adjusting the interfacial adhesion via surface modification to prepare high-performance fibers

Ultra-high molecular weight polyethylene(UHMWPE)fiber is a new kind of high-performance fiber.Due to its excellent physical and chemical characteristics,it is widely used in various fields.However,the surface UHMWPE fiber is smooth and demonstrates no-polar groups.The weak interfacial adhesion between fiber and resin seri-ously restricts the applications of UHMWPE fiber.Therefore,the surface modification treatments of UHMWPE fiber are used to improve the interfacial adhesion strength.The modified method by adding nanomaterials elu-cidates the easy fabrication,advanced equipment and proper technology.Thus,the progress of UHMWPE nanocomposite fibers prepared via adding various nanofillers are reviewed.Meanwhile,the effects of other various methods on surface modification are also reviewed.This work advances the various design strategies about nano technologies on improving interfacial adhesion performance via treatment methodologies.

Tuning the particle size and morphology of high energetic material nanocrystals

Morphology controlled synthesis of nanoparticles of powerful high energetic compounds(HECs) such as l,3,5-trinitro-l,3,5-triazinane(RDX) and 1,3,5,7-tetranitro-l,3,5,7-tetrazocane(HMX) were achieved by a simple solvent—antisolvent interaction(SAI) method at 70 ℃.The effects of different solvents on particle size and morphology of the prepared nano-HECs were studied systematically.Particle size and morphology of the nano-HECs was characterized using field emission scanning electron microscopy(FE-SEM) imaging.X-ray diffraction(XRD) and Fourier transform infrared(FTIR) spectroscopy studies revealed that RDX and HMX were precipitated in their most stable polymorphic forms,i.e.a and P,respectively.Thermogravimetric analysis coupled with differential scanning calorimetry(TGA-DSC) studies showed that the thermal response of the nanoparticles was similar to the respective raw-HECs.HEC nanoparticles with spherical and rod shaped morphology were observed under different solvent conditions.The mean particle size also varied considerably with the use of different solvents.

Statistical evaluation and optimization of zinc electrolyte hot purification process by Taguchi method

The neutral zinc sulfate solution obtained from hydrometallurgical process of Angouran zinc concentrate has cadmium, nickel and cobalt impurities, that must be purified before electrowinning. Therefore, cadmium and nickel are usually cemented out by addition of zinc dust and remained nickel and cobalt cemented out at second stage with zinc powder and arsenic trioxide. In this research, a new approach is described for determination of effective parameters and optimization of zinc electrolyte hot purification process using statistical design of experiments. The Taguchi method based on orthogonal array design(OAD) has been used to arrange the experimental runs. The experimental conditions involved in the work are as follows: the temperature range of 70-90 ℃ for reaction temperature(T), 30-90 min for reaction time(t), 2-4 g/L for zinc powder mass concentration(M), one to five series for zinc dust particle size distributions(S1-S5), and 0.1-0.5 g/L(C) for arsenic trioxide mass concentration. Optimum conditions for hot purification obtained in this work are T4(85 °C), t4=75 min, M4=3.5 g/L, S4(Serie 4), and C2=0.2 g/L.

Low-cost high entropy alloy(HEA)for high-efficiency oxygen evolution reaction(OER)

Oxygen evolution reaction(OER)is the key step involved both in water splitting devices and rechargeable metal-air batteries,and hence,there is an urgent need for a stable and low-cost material for efficient OER.In the present investigation,Co-Fe-Ga-NiZn(CFGNZ)high entropy alloy(HEA)has been utilized as a low-cost electrocatalyst for OER.Herein,after cyclic voltammetry activation,CFGNZ-nanoparticles(NPs)are covered with oxidized surface and form high entropy(oxy)hydroxides(HEOs),exhibiting a low overpotential of 370 mV to achieve a current density of 10 mA/cm^(2)with a small Tafel slope of 71 mV/dec.CFGNZ alloy has higher electrochemical stability in comparison to state-of-the art RuO2 electrocatalyst as no degradation has been observed up to 10 h of chronoamperometry.Transmission electron microscopy(TEM)studies after 10 h of long-term chronoamperometry test showed no change in the crystal structure,which confirmed the high stability of CFGNZ.The density functional theory(DFT)based calculations show that the closeness of d(p)-band centers to the Fermi level(EF)plays a major role in determining active sites.This work highlights the tremendous potential of CFGNZ HEA for OER,which is the primary reaction involved in water splitting.

Surface defect engineering of metal oxides photocatalyst for energy application and water treatment

Despite metal oxides offer excellent characteristics in the field of photocatalysis,they often suffer from charge carrier recombination as well as limited visible response,which indeed reduce the charge kinetics process and ultimately reduce the photocatalytic output.Defect engineering is a sophisticated technique to manufacture defects and alter the geometric structure and chemical environment of the host.The present study provides an all-inclusive outline of recent developments on the classification of metal oxide defects based on the dimensions of a host crystal lattice.Precisely,surface modification of metal oxides through 0D(point),1D(line),2D(planar),and 3D(volume)defects with their subsequent mechanism and impact on photocatalytic performance are presented.By wisely amending the morphology(cores along with the shells)and electronic structure of metal oxide photocatalysts(TiO_(2),ZnO,Bi_(2)O_(3),Fe_(2)O_(4) etc.)through different attuned and veritable approaches,their photocatalytic activity can be substantially improved.Optimal studies on defect engineering not only expose the altered physicochemical features but also modulate the electron-hole pair dynamics,stability,and active radical production for various photoredox reactions.Altered atomic,as well as electronic configuration,facilitated a photocatalyst material to have different optical features,adsorption properties along with improved carrier transfer as well as isolation rate.Thus,the systematic exploration of photocatalytic rudiments of defect rich metal oxide for various applications such as H_(2) evolution,CO_(2) reduction,pollutant degradation,and bacterial disinfection could bring significant research advancement in this field.

Improving the photocatalytic performance of TiO2 via hybridizing with graphene

In this paper an improvement in the photocatalytic performance of TiO2 was carried out via hybridizing with graphene.Graphene-TiO2（GR-TiO2/nanocomposites with different weight addition ratios of graphene oxide（GO）have been prepared via a facile microwave irradiation of GO and tetrabutyl titanate in isopropyl alcohol.Raman spectroscopy（RS）,X-ray diffraction（XRD）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,UV–visible spectroscopy（UV–vis）,Fourier transform infrared spectra（FTIR）,energy dispersive X-ray spectroscopy（EDX）and photoluminescence spectra（PL）are employed to determine the properties of the samples.Microwave irradiation can heat the reactant to a higher temperature in a short time,simultaneously GO is reduced to graphene and TiO2 nanoparticles grown on the surface of GR.GR-TiO2 nanocomposites synthesized via this approach have efficient electron conductivity in GR,resulting in a reduced electron–hole recombination rate.Among the synthesized nanocomposites,GT-8wt% exhibited the best photocatalytic activity toward photocatalytic degradation of MB.Our current work provides a new insight for the fabrication of GR-TiO2 nanocomposites within a short reaction time and also explains the mechanism of photocatalysis employing radical and hole scavengers.

Effect of carbon-doping on structural and dielectric properties of zinc oxide

In this paper,Carbon-doped Zinc Oxide(C-ZnO)samples were prepared using the solid-state reaction method.The influence of carbon-doping on the structural and dielectric properties of ZnO samples was studied.The shift in the highest peak position(101)in XRD patterns of carbon-doped samples was observed.The Raman peak at 581 cm^(-1) in undoped ZnO was shifted and broadened in carbon-doped ZnO samples.The ZnO samples doped with carbon show higher values of dielectric constant(~2400 at 1 kHz)compared to pure ZnO(~9 at 1 kHz)which was due to increase in native point defects in the samples.The ac conductivity(σ_(ac))value of the carbon-doped sample was enhanced by 103 times for((ZnO)_(0.9) C_(0.1))sample.