Wet Mixing Method Research Articles

Enhanced lithium and electron diffusion of LiFePO4 cathode with two-dimensional Ti3C2 MXene nanosheets

Novel LiFePO4/Ti3C2 composite (LFP/TC) cathodes have been prepared via a simple wet mixing method followed by a heat treatment at 400 °C. Ti3C2 nanosheets bridge the LiFePO4 nanoparticles to form an integrated conductive network via the “plane-to-point” conducting mode. This conductive network acts as short pathways for the diffusion of both lithium ion and electron in the composite cathode. Thus, the electronic and ionic conductivities are simultaneously enhanced, leading to the improved electrochemical properties of LFP/TC composites. Thereinto, the LFP/TC composite with 2 wt% Ti3C2 (LFP/TC2) delivers the highest initial discharge capacity of 159 mAh g−1 at 0.1 C as well as the best rate performance with a high reversible capacity of 86 mAh g−1 at 5 C. Meanwhile, the LFP/TC2 composite also holds the superior capacity retention of 96% at 1 C after 100 cycles. The results demonstrate that LFP/TC composite has promising practical applications as the cathode material in the high-power lithium-ion batteries.

Investigation of Performance of Soil-Cement Pile in Support of Foundation Systems for High-Rise Buildings

This paper presents the experimental study of Soil-Cement Pile (SCpile) by wet mixing method in sandy soils, with the typical project at An Trung Complex apartment, Da Nang city, Vietnam. With the characteristic of soil layers is sandy soil, the strength of laboratory stabilized soils with the amount of cement from 150¸300 kg/m3 was determined. Simultaneously, the authors also performed the experiments of 20 test piles collected from the site which has cement content about 280 kg/m3 and the unconfined compressive strength qu= (4.5-6.0) MPa. After that, a full-scale model static axial compressive load tests of two single piles and a group of four piles with diameter 800 mm and 12 m length were also conducted. The experiment results show that the bearing capacity of every single pile is 1.200 kN with settlement 6.93 mm and the group of four CSpiles is 3.200 kN with settlement 5.03 mm. The results presented in the paper illustrate that SCpile is the suitable solution for foundation construction process with low cost and saving time for high rise buildings. The result shows a capable application of soil cement piles for support of high-rise buildings.

Effect of Graphene Nanoplatelets on Microstructure and Mechanical Properties of AlSi10Mg Nanocomposites Produced by Hot Extrusion

In this research, AlSi10Mg composites reinforced with graphene nanoplatelets (GNPs) were fabricated in order to study the effect of GNPs on microstructure and mechanical properties of the AlSi10Mg alloy. The composites were produced by a wet mixing method followed by two-step hot consolidation (hot compaction then hot extrusion) at 673 K (400°C). The weight percentages of GNPs were 0.5 and 1 wt.% with respect to the AlSi10Mg alloy. Tensile and Vickers hardness tests at room temperature were performed to evaluate the effect of GNPs on mechanical properties of asfabricated composite. The outcomes show that the high quantity of GNPs (>0.5 wt.%) deteriorates the mechanical properties of AlSi10Mg composite due to the agglomeration of GNPs and, as a consequence, introduction of internal porosity in the composite. However, it is found that relatively low fraction of GNPs can uniformly be dispersed in the Al alloy matrix through the wet mixing method. The hardness and tensile results demonstrated that the mechanical properties improve slightly through the addition of 0.5 wt.% of GNPs, while 1.0 wt.% GNPs addition did not lead to improved performance owing to overwhelming effects of porosity.

Performance of zeolite ceramic membrane synthesized by wet mixing method as methylene blue dye wastewater filter

Problem of pollution in water continues in Indonesia, with its manufacturing sector as biggest contributor to economic growth. One out of many technological solutions is post-treating industrial wastewater by membrane filtering technology. We presented a result of our fabrication of ceramic membrane made from zeolite with simple mixing and he. At 5% of (poring agent):(total weight), its permeability stays around 2.8 mD (10−14m2) with slight variance around it, attributed to the mixture being in far below percolating threshold. All our membranes achieve remarkable above 90% rejection rate of methylene blue as solute waste in water solvent.

Characterization of Interfacial Bonding Mechanism for Graphene-Modified Powder Metallurgy Nickle-Based Superalloy

A modified FGH96 superalloy using 0.1 wt% graphene was successfully prepared using the wet mixing method. The interfacial bonding mechanism between the graphene and the superalloy matrix was characterized using optical microscope, scanning electronic microscope, transmission electronic microscope and X-ray tomography. The results revealed that the graphene could be dispersed uniformly inside the matrix of the superalloy, and the bonding interface between graphene and the superalloy showed a rather diffusion instead of abrupt distinction, suggesting that the interface was formed via chemical fusion rather than a mechanical combination. The uniform dispersity of the graphene inside the superalloy matrix could improve the tensile properties significantly, including tensile strength, plasticity and yield strength. The existence of the graphene at the fracture surface further verified that the graphene could increase the effective bearing force of the material during the tensile test.

High sensitivity and selectivity of CaCu3Ti4O12-ZnO composites towards acetone gas at room temperature

Detection of low concentration of acetone gas was carried out using porous CCTO-ZnO composites. The CCTO-ZnO composites were prepared via wet mixing method. The effects of ZnO (x = 0, 2, 6, and 10wt%) addition on the structural, morphological, and optical properties of CCTO-ZnO powder were investigated by XRD, FTIR, FESEM-EDAX, BET, UV–vis, respectively, whereas the acetone gas sensing properties of CCTO-ZnO composites were studied by I-V characteristic. The XRD result showed a polycrystalline structure. The surface morphology of the powder exhibited a uniform distribution with intergranular porous microstructures. BET indicated average pore diameter (10.08, 10.70, 12.91, and 13.76nm) and surface area (1.003 1.038, 1.594, and 2.029m2g−1), respectively with increasing amount of ZnO. This is the cause for the reduction of optical transmittance and increase in their energy bandgap (1.97, 2.05, 2.08, and 2.10eV). All samples depicted good transparency (≤ 80%) in the visible region. CCTO with the addition of 10wt% ZnO composite showed the highest sensitivity and selectivity towards 1ppm acetone gas. The composites had 1% error from earlier stability performance, and can possibly be utilized for practically applied in the detection of acetone gas.

Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectroscopy as an Analytical Method to Investigate the Secondary Structure of a Model Protein Embedded in Solid Lipid Matrices.

Protein drugs may encounter conformational perturbations during the formulation processing of lipid-based solid dosage forms. In aqueous protein solutions, attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy can investigate these conformational changes following the subtraction of spectral interference of solvent with protein amide I bands. However, in solid dosage forms, the possible spectral contribution of lipid carriers to protein amide I band may be an obstacle to determine conformational alterations. The objective of this study was to develop an ATR FT-IR spectroscopic method for the analysis of protein secondary structure embedded in solid lipid matrices. Bovine serum albumin (BSA) was chosen as a model protein, while Precirol AT05 (glycerol palmitostearate, melting point 58 ℃) was employed as the model lipid matrix. Bovine serum albumin was incorporated into lipid using physical mixing, melting and mixing, or wet granulation mixing methods. Attenuated total reflection FT-IR spectroscopy and size exclusion chromatography (SEC) were performed for the analysis of BSA secondary structure and its dissolution in aqueous media, respectively. The results showed significant interference of Precirol ATO5 with BSA amide I band which was subtracted up to 90% w/w lipid content to analyze BSA secondary structure. In addition, ATR FT-IR spectroscopy also detected thermally denatured BSA solid alone and in the presence of lipid matrix indicating its suitability for the detection of denatured protein solids in lipid matrices. Despite being in the solid state, conformational changes occurred to BSA upon incorporation into solid lipid matrices. However, the extent of these conformational alterations was found to be dependent on the mixing method employed as indicated by area overlap calculations. For instance, the melting and mixing method imparted negligible effect on BSA secondary structure, whereas the wet granulation mixing method promoted more changes. Size exclusion chromatography analysis depicted the complete dissolution of BSA in the aqueous media employed in the wet granulation method. In conclusion, an ATR FT-IR spectroscopic method was successfully developed to investigate BSA secondary structure in solid lipid matrices following the subtraction of lipid spectral interference. The ATR FT-IR spectroscopy could further be applied to investigate the secondary structure perturbations of therapeutic proteins during their formulation development.

New Nanocomposite Materials with Improved Mechanical Strength and Tailored Coefficient of Thermal Expansion for Electro-Packaging Applications

In this research, copper nanocomposites reinforced by graphene nanoplatelets (GNPs) were fabricated using a wet mixing method followed by a classical powder metallurgy route. In order to find the best dispersion technique, ball milling and wet mixing were chosen. Qualitative evaluation of the structure of the graphene after mixing indicated that the wet mixing is an appropriate technique to disperse the GNPs. Thereafter, the influence of graphene content on microstructure, density, hardness, elastic modulus, and thermal expansion coefficient of composites was investigated. It was shown that by increasing the graphene content the aggregation of graphene is more obvious and, thus, these agglomerates affect the final properties adversely. In comparison with the unreinforced Cu, Cu–GNP composites were lighter, and their hardness and Young’s modulus were higher as a consequence of graphene addition. According to the microstructural observation of pure copper and its composites after sintering, it was concluded that grain refinement is the main mechanism of strengthening in this research. Apart from the mechanical characteristics, the coefficient of thermal expansion of composites decreased remarkably and the combination of this feature with appropriate mechanical properties can make them a promising candidate for use in electronic packaging applications.

A Novel Approach to Enhance the Mechanical Strength and Electrical and Thermal Conductivity of Cu-GNP Nanocomposites

Copper/graphene nanoplatelet (GNP) nanocomposites were produced by a wet mixing method followed by a classical powder metallurgy technique. A qualitative evaluation of the structure of graphene after mixing indicated that wet mixing is an appropriate dispersion method. Thereafter, the effects of two post-processing techniques such as repressing–annealing and hot isostatic pressing (HIP) on density, interfacial bonding, hardness, and thermal and electrical conductivity of the nanocomposites were analyzed. Density evaluations showed that the relative density of specimens increased after the post-processing steps so that after HIPing almost full densification was achieved. The Vickers hardness of specimens increased considerably after the post-processing techniques. The thermal conductivity of pure copper was very low in the case of the as-sintered samples containing 2 to 3 pct porosity and increased considerably to a maximum value in the case of HIPed samples which contained only 0.1 to 0.2 pct porosity. Electrical conductivity measurements showed that by increasing the graphene content electrical conductivity decreased.

Sustainable Production of High-Purity Hydrogen by Sorption Enhanced Steam Reforming of Glycerol over CeO2-Promoted Ca9Al6O18–CaO/NiO Bifunctional Material

The present work investigates the sustainable production of high-purity hydrogen through sorption enhanced steam reforming of glycerol (SESRG) over Ca9Al6O18–CaO/xNiO (x = 15, 20, and 25 wt %) and Ca9Al6O18–CaO/20NiO–yCeO2 (y = 5, 10, and 15 wt %) bifunctional catalyst-sorbent materials. A wet mixing method involving limestone acidification coupled with two-step calcination was employed to prepare the bifunctional materials. Cyclic carbonation/calcination tests revealed that the bifunctional materials promoted with 10 and 15 wt % of CeO2 possessed an excellent CaO conversion (97% in both cases) and a remarkable cyclic stability (up to 15 cycles). This was mainly attributed to the thin shell-connected structure formed by the addition of CeO2 and the oxygen mobility characteristic of CeO2. The use of Ca9Al6O18–CaO/xNiO materials in five consecutive SESRG/regeneration cycles revealed that they suffered from fast deactivation mainly due to CaO sintering and coke deposition. Despite the high H2 purity obtained...

A Novel Cu–GNPs Nanocomposite with Improved Thermal and Mechanical Properties

Classical powder metallurgy followed by either hot isostatic pressing (HIPing) or repressing–annealing process was used to produce Cu–graphene nanoplatelets (GNPs) nanocomposites in this work. A wet mixing method was used to disperse the graphene within the matrix. The results show that a uniform dispersion of GNPs at low graphene contents could be achieved, whereas agglomeration of graphene was revealed at higher graphene contents. Density evaluations showed that the relative density of pure copper and copper composites increased by using the post-processing techniques. However, it should be noticed that the efficiency of HIPing was remarkably higher than repressing–annealing process, and through the HIPing, fully dense samples were achieved. The Vickers hardness results showed that the reconsolidation steps can improve the mechanical strength of the specimens up to 50% owing to the progressive porosity elimination after reconsolidation. The thermal conductivity results of pure copper and composites at high temperatures showed that the post-processing techniques could enhance the conductivity of materials significantly.

Evaluation of volume compressibility coefficient variations incement stabilized bentonite clay using (wet & dry)

According to the constituent materials of soil layers in the project area, different Sites exhibitdifferent behaviorstowards compressibility. Mechanical and hydraulic behaviors of layers composed of coarse aggregates such as sand and gravel are very more predictable than those of layers composed of fine aggregates, especially clay. The settlement in such soilsinvolve time parameters and it is possible to calculate and evaluatethe parameters using the common tests in geotechnical engineering. The coefficient of volume compressibility is an important parameter for calculating the consolidation settlement of clay layers, which can be calculatedby means of the one-dimensional consolidation test device. In this study, 2,4,6,8 and 10% of cement at treatment times of 7,14 and 28 days were used to stabilize the bentonite clay. All samples prepared by wet and dry method hadthe same moisture contents in the mentioned levels equal to the liquid limit moisture of the original soil. The studied soil falls in the group CH with the liquid limit of 132% based on the unified classification system. The results obtained in this study indicated that the changes in pressure applied on the soil exhibited a significant impact on the performance of stabilizers and generally, the effects of wet and dry mixing methods on the coefficient of volume compressibility, and consequently,on the settlement could be seen

Thermogravimetric and kinetics investigation of pine wood pyrolysis catalyzed with alkali-treated CaO/ZSM-5

In this study, the characteristics of thermal decomposition of Wyoming pine wood catalyzed with CaO/ZSM-5 was investigated by using a thermogravimetric analyzer (TGA). The CaO/ZSM-5 catalyst was prepared using a wet mixing method aided by an ultrasonic treatment to improve the dispersing uniformity of CaO on ZSM-5. Material characterizations such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption and desorption isotherms test, and scanning electron microscopy (SEM)/energy dispersive spectrometer (EDS) were carried out to examine thoroughly the CaO/ZSM-5 catalyst. The kinetic parameters and activation energy were determined using the Flynn-Wall-Ozawa (FWO) and Kissinger-Akahire-Sunose (KAS) methods. Results indicate that the yields and conversion of pine wood pyrolysis with CaO/ZSM-5 catalyst addition are much higher than that of pine wood individually. Further, the effect of CaO/ZSM-5 catalyst addition on the activation energy distribution of pine wood pyrolysis is presented and discussed in detail.

Development of Al- and Cu-based nanocomposites reinforced by graphene nanoplatelets: Fabrication and characterization

Aluminum and copper matrix nanocomposites reinforced by graphene nanoplatelets (GNPs) were successfully fabricated by a wet mixing method followed by conventional powder metallurgy. The uniform dispersion of GNPs within the metal matrices showed that the wet mixing method has a great potential to be used as a mixing technique. However, by increasing the GNPs content, GNPs agglomeration was more visible. DSC and XRD of Al/GNPs nanocomposites showed that no new phase formed below the melting point of Al. Microstructural observations in both nanocomposites reveal the evident grain refinement effect as a consequence of GNPs addition. The interfacial bonding evaluation shows a poor interfacial bonding between GNPs and Al, while the interfacial bonding between Cu and GNPs is strong enough to improve the properties of the Cu/GNPs nanocomposites. In both composites, the coefficient of thermal expansion decreases as a function of GNPs while, their hardness is improved by increasing the GNPs content as well as their elastic modulus.

Composite Based Chitosan/Zinc-Doped HA as a Candidate Material for Bone Substitute Applications

The composite based Zinc-doped in Chitosan/Hydroxyapatite was successfully prepared by wet mixing method through the addition of 10, 15, and 20wt% of chitosan. The addition of Chitosan increased the compressive strength and the modulus elasticity. However, it decreased the density and the surface hardness of HA-Zn. Mechanical characterization revealed that these composites are suitable as a candidate of a cancellous bone substitute. Composite with 10% chitosan has compressive strength and modulus elasticity of 57.03 MPa and 0.15 GPa, respectively. Hence, it has the physical and mechanical properties that meet the standards as a cancellous bone substitute material. Also, in vitro biocompatibility test against BHK-21 cells exhibited non-toxic materials.

The Effect of Rare Earth Dopants in Crystal Structure of Bi-2212 Superconductor

Bi2Sr2CaCu2O8+∂ samples have been successfully synthesized by doping rare earth (RE) variations using wet-mixing method. Samples calcined at 600°C for 3 hours and sintered at 850°C for 10 hours. The purpose of research is to determine the effect of the RE dopant on the microscopic structure of BSCRECO superconductors. Therefore, the research was conducted characterization by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Measurements with XRD could be carried out and crystal system of Bi2Sr2CaCu2O8+∂ with rare earth (RE) dopants could be determined clearly. Generally, crystallization has occurred very well demonstrated by the diffraction peaks are sharp, which is dominated by the emergence of Bi-2212 phase. Search match results of XRD spectrum showed Bi2Sr2CuOx (2201) and Ca2CuO3 (21) as an impurity phase with small intensity. Also, that is showing volume fraction from 85 to 92% and orthorombic value for all samples from 5 to 7%. The effect of RE dopants resulted a shift angle 2θ and changes in the volume of the unit cells of each sample. The value of the unit cell volume of the largest to smallest is BS(CN)CO, BS(CNG)CO, BS(CNEG)CO, BS(CNE)CO, BS(CG)CO, BS(CEG)CO and BS(CE)CO. Measurement with FTIR showed the bending vibration absorption by CO32- in the wavelength range between 1500 and 1520 cm-1, vibration of M-O between 420 and 650 cm-1, the complex formation of BSCCO in the wavelength range between 1690 and 1700 cm-1. Measurement with SEM showed rod shape with particle size in hundreds nanometer.

Settlement control by deep and mass soil mixing in clayey soil

This paper discusses the influence of adding various amounts of cement to and changing the water content of clayey soil and their effects on controlling the settlement of a superstructure with various improvement area ratios (IARs). As a first step, the physical and mechanical properties of clayey soil from Bandar Imam Port, Iran, with 4, 6, 8 and 10% cement content and various water contents (30, 48 and 70%) were determined. Sample preparation was carried out using the wet deep soil mixing (DSM) method. The relationship between secant modulus at 50% strength (E50) and curing time for various cement contents was determined. In addition, different DSM column patterns with IARs of 0, 0·2, 0·3, 0·4 and 0·5, considering floating and end bearing DSM columns, were modelled using the finite-element method. Soil improvement by mass mixing of layers 2–7 m thick was also studied. The optimisation of various IARs and DSM characteristics and patterns enables production of a chart guide for preliminary design.

An Investigation on the Sinterability and the Compaction Behavior of Aluminum/Graphene Nanoplatelets (GNPs) Prepared by Powder Metallurgy

In the present study, the densification response of Al matrix reinforced with different weight percentages (0, 0.5, 1.0, 1.5 and 2.0 wt.%) of graphene nanoplatelets (GNPs) was studied. These composites were produced by a wet method followed by a conventional powder metallurgy. The Raman spectrum of graphene indicates that preparation of the composites through the wet mixing method did not affect the disordering and defect density in the GNPs structure. The nanocomposite powder mixture was consolidated via a cold uniaxial compaction. The samples were sintered at different temperatures (540, 580 and 620 °C) under nitrogen flow so as to assess the sinterability of the nanocomposites. X-ray diffraction (XRD) has been carried out to check the possible reaction between GNPs and aluminum. According to the XRD patterns, it seems that Al4C3 did not form during the fabrication process. The relative density, compressibility, sinterability and Vickers hardness of the nanocomposites were also evaluated. The effects of GNPs on the consolidation behavior of the matrix were studied using the Heckel, Panelli and Ambrosio Filho, and Ge equations. The outcomes show that at early stage of consolidation the rearrangement of particles is dominant, while by increasing the compaction pressure, due to the load partitioning effect of GNPs, the densification rate of the powder mixture decreases. Moreover, the fabricated nanocomposites exhibited high Vickers hardness of 67 HV5, which is approximately 50% higher than monolithic aluminum. The effect of graphene addition on the thermal conductivity of Al/GNPs nanocomposites was evaluated by means of thermal diffusivity measurement, and the results showed that the higher thermal conductivity can be only achieved at lower graphene content.

Sorption enhanced steam methane reforming by Ni–CaO materials supported on mayenite

Sorption enhanced steam methane reforming (SESMR), i.e. SMR with in situ CO2-sorption, can lead to a sustainable and economical exploiting of natural gas for hydrogen production, with high purity and simultaneous sequestration of greenhouse gases. CaO-mayenite CO2-sorbents, Ni-mayenite SMR catalysts and Ni–CaO-mayenite combined sorbent catalyst materials (CSCM) for SESMR were synthesized by wet mixing and wet impregnation methods, and characterized by means of XRD, BET/BJH, SEM/EDS, and TPR. For CSCM, an influence of CaO load on textural and Ni reducibility properties was recorded. Materials sorption capacity was measured in multicycles sorption/regeneration TGA tests: it always underwent a stabilization with cycle number increase. Reforming tests in micro-reactor scale were performed on 3 wt% to 10 wt% Ni-mayenite and selected CSCM: all Ni-mayenite always shown good performances, while for CSCM a detrimental role of CaO load on Ni catalytic activity was evidenced.

Synthesis and Characterization of GLBCO-123 Phase: Gd<sub>1-x</sub>L<sub>x</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub> (x = 0.0 - 0.5)

Investigation of the substitution process can provide a better understanding of the superconducting mechanisms in cuprous oxide materials. In this work the effects of substitution Lanthanum (La) for Gadolinium (Gd) on the structure and oxygen content for x = 0.0 - 0.5 in the compound Gd1-xLaxBa2Cu3O7-δ (GLBCO-123 phase) have been investigated. Samples were synthesized by using a wet-mixing method from powders of Gd2O2, La2O2, BaO, CuO, and solution of HNO3. Based on the analysis of XRD data and SEM-EDXA, it confirms that the sample has formed the GLBCO-123 phase, as expected. It has been obtained that the lattice parameters a and c are increased while the parameter b is slightly decreased with increasing content of Lanthanum. The oxygen content slightly decreased and structure of the Gd1-xLaxBa2Cu3O7-δ phase changed from orthorhombic to tetragonal with increasing the content of Lanthanum.