Matrix Micro Research Articles

Experimental Study on Mechanical, Chemical and Acoustical Properties of Waste Tea Leaf Fiber Reinforced Epoxy Composites

Fibre reinforced polymer composites are employed instead of metal and wood because they are stronger, more lightweight, have a favourable strength to weight ratio, and are noncorrosive. In the current research, sisal, carbon fibre, and industrial waste tea leaf fibre (WTLF) reinforced hybrid epoxy composites are being examined for their chemical, mechanical and acoustical properties with experimental study. The sisal and WTLF were chemically treated with 5% sodium hydroxide (NaOH) solution. By modifying the weight percentage of sisal and WTLF with a structure of 40 weight percent fibre and 60 weight percent matrix, five different compositions of natural fibre reinforced hybrid composites were fabricated using an automatic compression moulding technique. As per the ASTM standard the manufactured hybrid composites are tested for mechanical, chemical and acoustic characteristics. According to the experimental findings, sisal fibre with a 25 wt% and WTLF with a 5 wt% demonstrated superior mechanical properties, while these materials also demonstrated an excellent acoustic absorption coefficient (AAC) of 0.62 between the frequency range of 2000 to 6300 Hz. The morphology of failure samples revealed the matrix micro crack, void formation, fiber pullout and layers of fractured fibers which are being examined using Scanning Electron Microscopy (SEM). The superior bonding between fibre and matrix was seen in the FTIR study of 5% alkali treated composites.

Investigations On Mechanical Properties Of Micro Particulates (Al2O3/B4C) Reinforced In Aluminium 7075 Matrix Composite

Metal Matrix Micro Composites (MMMCs), with the addition of micro-particulate reinforcements, can be significant for automobile, aerospace and numerous applications due to their low density and good mechanical properties, better corrosion and wear resistance, and low coefficient of thermal expansion compared to conventional materials. Designing the metal matrix composite material aims to combine the desirable attributes of metals and ceramics. The present work is focused on studying the mechanical properties of Aluminium alloy (7075) with Al2O3 and B4C micro-composite produced by the Stir Casting method. Different % age of reinforcement is used. The Stir casting technique is used to achieve a uniform dispersion of micro-particulate Al2O3 and B4C in molten aluminium alloy. A tensile test, Hardness test, and Impact test were performed on the samples obtained by the fabrication processes. A microstructural study will be carried out through an optical Microscope to know the distribution of Al2O3 and B4C micro particulates in Al alloy.

A Compact Amorphous In-Ga-Zn-Oxide Thin Film Transistor Pixel Circuit With Two Capacitors for Active Matrix Micro Light-Emitting Diode Displays

In this paper, we propose a novel amorphous In-Ga-Zn-oxide (a-IGZO) thin film transistor (TFT) pixel circuit for pulse width modulation (PWM) driving active matrix micro light-emitting diode (μLED) displays. The proposed pixel circuit compensates for wavelength shifts according to gray level and threshold voltage (VTH) variation of TFTs with only two capacitors. This compact operation can be achieved by simultaneous compensation for VTH along with data input in the constant current generation (CCG) circuit and the PWM circuit, which consist the pixel. Since the VTH variation in TFTs is compensated, the proposed pixel circuit can supply a uniform and stable current to the μLED throughout all gray levels. The compensation accuracy was verified by HSPICE with an oxide TFT model based on the measurement data. In addition, we analyzed the optimization method to improve the PWM driving by controlling the electrical properties of TFT, and verified this approach by simulation.

Advanced Active Matrix Micro LED Driving Technology with Thin Film Transistors

Advanced Active Matrix Micro LED Driving Technology with Thin Film Transistors

3200 ppi Matrix-Addressable Blue MicroLED Display.

In this article, an active matrix (AM) micro light-emitting diode (MicroLED) display with a resolution of 1920 × 1080 and a high pixel density of 3200 pixels per inch (ppi) is reported. The single pixel with a diameter of 5 μm on the MicroLED array exhibits excellent characteristics, including a forward voltage of 2.8 V at 4.4 μA, an ideality factor of 1.7 in the forward bias of 2–3 V, an extremely low leakage current of 131 fA at −10 V, an external quantum efficiency of 6.5%, and a wall-plug efficiency of 6.6% at 10.2 A/cm2, a light output power of 28.3 μW and brightness of 1.6 × 105 cd/m2 (nits) at 1 mA. The observed blue shift in the electroluminent peak wavelength is only 6.6 nm from 441.2 nm to 434.6 nm with increasing the current from 5 μA to 1 mA (from 10 to 5 × 103 A/cm2). Through flip-chip bonding technology, the 1920 × 1080 bottom-emitting MicroLED display through the backside of a sapphire substrate can demonstrate high-resolution graphic images.

Investigation on wear behavior of aluminium matrix micro and nanocomposites

Aluminum matrix composites (AMCs) have a wide range of applications in aerospace, marine, and automobile because of their improved tribological and mechanical properties. In the present article, Al7075 alloy was used as the matrix material filled with micro (average size 50 μm) and nano (average size 80 nm) particles of Al2O3 (alumina). The same quantity of weight fractions of micro and nano alumina particles were injected into the semi-solid state of Al7075 aluminum alloy by the mechanical stir casting process. The developed composites have been investigated for specific wear rate (SWR) by using Pin on Disc Tribometer. The results of nano and micro composites have been compared at similar combinations of input parameters. The normal load, sliding distance, and sliding velocity were the input parameter for analyzing the SWR. The result shows that SWR increased with an increase in normal load and sliding distance. It has been found from the results that SWR is inversely proportional to sliding velocity. Also, results indicate that SWR of the developed AMCs containing nano alumina was found superior to that of the micro composite and base material.

Electrochemical corrosion and erosive wear behaviour of microwave processed WC-10Co4Cr clad on SS-316

WC-10Co4Cr cladding over an austenitic stainless steel (SS-316) was fabricated by using a cost- effective microwave technique. Cladding was performed with 1.20 kW power and a frequency of 2.45 GHz in an industrial microwave oven. The XRD surveillance reveals a cluster of carbide phases adjunct to W-Cr-Fe based hexagonal matrix. The SEM examination reveals a solid microstructure and a homogeneous reinforced skeleton with porosity measures of less than 1% in the clad specimen. Tungsten (W) distributed equally in matrix and carbides, resulting in bulk hardness and matrix micro hardness increasing gradually and reaching a peak at 750HV, respectively, which is significantly greater than the base metal (SS-316) hardness (about 220HV). The clads erosive wear was measured at various impact angles (30°, 60°, and 90°) by utilizing a solid particle erosion with alumina as the erodent. In addition, corrosion testing found that in the NaCl solution of 3.5 wt% the cladded specimen exhibited the less corrosion resistance than that of the base metal.

A new progressive damage model for predicting the tensile behavior of the three-dimensional woven carbon/carbon composites using micromechanics method

A new progressive damage model for the three-dimensional (3 D) woven carbon/carbon (C/C) composites is developed at fiber-matrix level using the micromechanics method. A woven architecture based Representative Volume Element (RVE) model composed of yarns, matrix and yarn/matrix interface is constructed, in which the manufacturing void defects are accounted for. The fiber-matrix concentric cylinder model is employed as a repeating unit cell to represent the yarn, and the matrix micro strain field is computed analytically by the micromechanics method. The maximum stain criteria is utilized for fiber longitudinal breakage, and the Von-Mises criterion is applied for the damage initiation of matrix in both intra-yarns and inter-yarns. The damaged fiber and matrix are modeled by the stiffness degradation method combined with exponential damage evolution equations. The zero thickness cohesive elements governed by bilinear traction-separation constitutive are adopted for yarn/matrix interfacial debonding behavior. The micro progressive damage and failure behavior of the 3 D woven C/C composites subjected to tension is implemented through a developed user-defined material subroutine in commercial software ABAQUS. The predicted stress-strain response is in a good agreement with experimental results. In addition, the effect of manufacturing void defects is also examined by the developed model.

Dielectric Behavior of Nano Lead - Nano Copper oxides Polyvinyl Chloride (PVC) Composites

The dielectric properties of pure PVC and pure PVC filled composites were performed to examine and characterize the structure of polymer composites. At room temperature the values of relative permittivity, loss factor, and ac conductivities were calculated as a function of frequency and it was found that incorporation of both micro and nano PbO and CuO with various wt% to the polymer matrix resulted in enhanced dielectric properties. The electrical response of polymer matrix micro- or nanocomposites show their conductivity and dielectric behavior. So the principal electrical character of polymers is insulating because of their very low concentration of free charge carriers, polymer nanocomposites (also called nanodielectrics) appear to be dielectrics or in other words, materials that will be polarized by applying an external electric field. Nano composites are closely associated with the development of cutting-edge electronic and optoelectronic devices. The nanoscale has been reached on the dimensional scale of electronic devices. The usefulness of polymer/inorganic molecule nanocomposites varies greatly, with various potential applications as well as different types of nanocomposites.

Modelling and analysing the water jet machining parameters of aluminium nano composite by ANOVA and Taguchi

Aluminium metal matrix micro composites and nano composites are widely used in industries such as aerospace and marine because of their combined mechanical properties. Al7075 alloy is the hardest material and machining such materials is quiet difficult by conventional methods. Water jet machining with abrasives flow technique is the mostly in usage of machining intricate shapes of hard aluminium MMCs and MMNCs. The variables of AJM process and their effects on kerf width and rate of material removal (MRR) were explained by experiments were designed using L18 Taguchi orthogonal array and parameters analysed using MINITAB software for acceptable results of simulation. Al7075 metal matrix nano SiC composite drilled by varying the flow rate of abrasives, pressure of the fluid flow, Stand-off distance and traverse speed of the jet and experiments conducted. Statistical tool, design of experiments has been accomplished for optimising the responses via Analysis of variance (ANOVA). The effect of individual parameters and interactions were analysed and the study revealed that the pressure and flow rate are influencing the kerf width whereas stand-off distance and pressure influencing the MRR.

Self validating Mueller matrix Micro-Mesoscope (SAMMM) for the characterization of biological media.

Reflectance Mueller matrix (MM) polarimetry is being used to characterize biological media in multiple clinical applications. The origin of the reflectance polarimetric data is often unclear due to the impact of multiple scattering and tissue heterogeneity. We have developed a new, to the best of our knowledge, multimodal imaging technique combining MM reflectance, MM digital confocal imaging, and co-registered nonlinear microscopy techniques. The instrument unveils the origin of reflectance polarimetric signature in terms of confocal reflectance data. The reconstructed reflected MM demonstrates the capability of our method to provide depth-resolved 3D polarization response from complex biological media in terms of depolarization, retardance, and orientation parameters.

Using New Micro Grafting Techniques in Grape

Micro-grafted Egyptian grapes were evaluated under in vitro conditions. In vitro Flame seedless cv. scions were grafted on Freedom rootstock shoots. Two methods were used for micro-grafting; alginate matrix and rhizogenic calli. Fluorescein stain was used to sap transport detection through vessels of both scion and rootstock. Biochemical and molecular analyses were used to evaluate successful micro-grafts. Obtained results showed that, In vitro derived shootlets had satisfactory growth. The culture of derived explants formed a successful graft union by alginate matrix (75%) compared to rhizogenic calli (50%) grown shootlets maintained by some roots and leaves formation. There was a significant difference between the two methods in forming a successful graft union and the subsequent growth-related traits. Grafted explants were tested to salinity stress of NaCl: CaCl2 1000, 2000 and 3000 ppm. The shoot and root related growth characteristics of the alginate matrix micro grafts were more tolerant to salinity than rhizogenic calli. However, raising salinity level led to growth decrease but alginate plantlets continued forming leaves. RAPD- PCR analysis cleared genetic changes in graft union area reflects a complete scion- rootstock combination, also a hereditary relationship with both was detected and proved micro-grafting success with the two methods. To sum up, micro-grafting is a suitable alternative propagation tool leading to higher growth potential of grafted plants and improving their ability to tolerate different stresses.

Evaluation of decellularization protocols for production of porcine small intestine submucosa for use in abdominal wall reconstruction.

Porcine-derived acellular biologic grafts are increasingly used in abdominal wall reconstruction and other soft tissue repairs. In a previous work, we have shown porcine small intestine submucosa (PSIS) exhibits clear advantages over porcine pericardium (PPC) and porcine acellular dermal matrix (PADM) in repairing full-thickness abdominal wall defects. In the present study, we aim to determine, quantify, and compare the effects of two most commonly used decellularization protocols on biomechanical and biocompatible properties of PSIS. After mechanical preparation, PSIS was treated with either alkaline and acid (AA) protocol or sodium dodecyl sulfate (SDS) protocol. Cellular content removal, preservation of matrix components, micro- and ultra- structures, and mechanical properties were compared. The host responses were evaluated using PSIS for repairing rat abdominal wall defects. With regard to the absence of cellular contents, neatly arranged collagen fiber structures, better retention of growth factors, better mechanical strength, lower degrees of local and systemic inflammatory responses, higher degree of vascularization and tissue ingrowth, alkaline and acid protocol exhibits clear advantages over SDS protocol for the preparation of PSIS extracellular matrix.

Research on Numerical Simulation of Gas Flow in Shale Matrix Micro Pore

In view of Longmaxi shale core in Sichuan basin, two-dimensional images of shale core were given by using scanning electron microscopy (SEM), and processed by ImageJ software to reconstruct the 3D shale matrix digital core, the digital core can reflect the nano pore structure more accurately. LBM model of gas flow in shale porous medium is established based on lattice Boltzmann method. The corresponding boundary conditions were established based on slip phenomenon for shale gas in porous medium micro flow, which can simulate gas flow in the micro pore in shale more realistic. The numerical results show that the microscale effect becomes obvious with the increase of Knudsen number, and the more obvious the non-Darcy phenomenon of gas flow in the shale matrix. The research results of this paper provide a theoretical basis for shale matrix permeability calculation, shale gas well productivity evaluation and development scheme design.

Low-velocity impact predictions of composite laminates using a continuum shell based modeling approach Part b: BVID impact and compression after impact

In this paper, a continuum shell based finite element (FE) model is introduced to predict the impact and compressive strength after impact (CSAI) response of fiber reinforced polymer matrix composite (FRPC) laminates of various traditional and non-traditional layup orientations. The FE model predicts the impact damage in the laminate. The impact results are then directly used to predict the CSAI of the structure. The model uses in-plane progressive damage and failure modeling coupled with discrete cohesive elements to capture the necessary failure mechanisms. Enhanced Schapery Theory captures the non-linearity due to matrix micro cracking as well as macro intra-lamina matrix cracking and fiber failure. Discrete cohesive elements are implemented to capture the inter-lamina failure initiation and propagation (delaminations). The numerical predictions are compared against impact and CSAI experimental data for composite laminates of various layups. A high quality post-impact inspection using ultrasound and micro-computed tomography (microCT) scanning was utilized for detailed comparison between model results and experiments. The modeling technique was seen to be highly capable of predicting the impact response and CSAI of multiple different stacking sequences using a general mesh.

Wafer‐scale monolithic hybrid integration of Si‐based IC and III–V epi‐layers—A mass manufacturable approach for active matrix micro‐LED micro‐displays

AbstractHybridization of silicon integrated circuits (ICs) with compound semiconductor device arrays are crucial for making functional hybrid chips, which are found to have enormous applications in many areas. Although widely used in manufacturing hybrid chips, the flip‐chip technology suffers from several limitations that are difficult to overcome, especially when the demand is raised to make functional hybrid chips with higher device array density without sacrificing the chip footprint. To address those issues, Beida Jade Bird Display Limited has developed its unique wafer‐level monolithic hybrid integration technology and demonstrated its advantages in making large‐scale hybrid integration of functional device arrays on Si IC wafers. Active matrix micro‐light‐emitting diode micro‐displays with a resolution of 5000+ pixel per inch were successfully fabricated using Beida Jade Bird Display Limited's monolithic hybrid integration technology. The general fabrication method is described, and the result is presented in this paper. The fabricated monochromatic micro‐light‐emitting diode micro‐displays exhibit improved device performance than do other micro‐display technologies and have great potentials in applications such as portable projectors and near‐to‐eye projection for augmented reality. More importantly, the wafer‐scale monolithic hybrid integration technology offers a clear path for low‐cost mass production of hybrid optoelectronic IC chips.

Particle Size and Particle Percentage Effect of AZ61/SiCp Magnesium Matrix Micro- and Nano-Composites on Their Mechanical Properties Due to Extrusion and Subsequent Annealing

Magnesium metal matrix composites (Mg MMCs) possess relatively more favorable mechanical properties than Mg alloys because they add reinforcements, such as small particles, short fibers, or continuous fibers, into the matrix. This study investigated the influence of adding different sizes and percentages of silicon carbide particles (SiCp) for manufacturing AZ61/SiCp Mg alloy composite extrusion plates on the mechanical properties of SiCp. We also examined the impact and discussed the evolution of microstructures, changes of material strength, ductility, formability, and other mechanical properties caused by a subsequent annealing treatment after plate extrusion. The results showed that the mechanical properties of plates can be improved by adding reinforcement particles. The effects of grain refinement were as follows: the smaller the size of the reinforcement particles, the greater the enhancement of mechanical properties. Among them, the AZ61/1 wt % SiCp/50 nm MMC plate had relatively excellent mechanical properties. Specifically, the ultimate tensile strength, yielding strength, ductility, hardness, and grain size of the plate were 331 MPa, 136.4 MPa, 43.1%, 62 HV, and 3.3 μm, respectively. Compared with SiCp-free Mg MMC plates, these properties of the AZ61/1 wt % SiCp/50 nm MMC plate were enhanced (or refined) by 6.4%, 3.4%, 83.4%, 2%, and 13.2%, respectively; by contrast, formability decreased by 9.1%.

Semi-analytical model based on generalized plane strain assumption for unidirectional composites with matrix micro cracks

ABSTRACTGeneralized plane strain state is assumed and stress-based finite strip method is formulated for analysis of unidirectional laminates with matrix microcracks. Total complementary potential energy is minimized and fourth-order Euler Lagrange governing equations are presented. This stress-based generalized plane strain approach analyzes general layup and loading conditions. It provides flexibility to control the number of finite strip nodal lines within each lamina; hence, stress behavior can be predicted across each lamina at the desired location of the structure. Along with all of the capabilities which are common with finite strip methodology based on plane strain assumption, this current work has extended the analysis of the cracked laminate. For example, by incorporating behavior of the out of the plane shear stress, boundary conditions including natural boundary conditions are imposed appropriately to solve governing Euler's equations. Results are compared with previously developed displacement-based formulation in the literature for cracked laminates. It has already been shown that a stress-based plane strain approach enhances variation-based cracked laminate analysis where only the case of cross-ply laminate under tension is considered. This current work applies generalized plane strain-based finite strip methodology to carry out analysis under different loading conditions.

Selective Plasma Etching of Polymeric Substrates for Advanced Applications.

In today’s nanoworld, there is a strong need to manipulate and process materials on an atom-by-atom scale with new tools such as reactive plasma, which in some states enables high selectivity of interaction between plasma species and materials. These interactions first involve preferential interactions with precise bonds in materials and later cause etching. This typically occurs based on material stability, which leads to preferential etching of one material over other. This process is especially interesting for polymeric substrates with increasing complexity and a “zoo” of bonds, which are used in numerous applications. In this comprehensive summary, we encompass the complete selective etching of polymers and polymer matrix micro-/nanocomposites with plasma and unravel the mechanisms behind the scenes, which ultimately leads to the enhancement of surface properties and device performance.

The Diametrically Loaded Cylinder for the Study of Nanostructured Aluminum–Graphene and Aluminum–Alumina Nanocomposites Using Digital Image Correlation

Non-contact methods for characterization of metal matrix composites have the potential to accelerate the development and study of advanced composite materials. In this study, diametrical compression of small disk specimens was used to understand the mechanical properties of metal matrix micro and nano composites. Analysis was performed using an inverse method that couples digital image correlation and the analytical closed form formulation. This technique was capable of extracting the tension and compression modulus values in the metal matrix nanocomposite disk specimens. Specimens of aluminum and aluminum reinforced with either Al2O3 nanoparticles or graphene nanoplatelets (GNP) were synthesized using a powder metallurgy approach that involved room temperature milling in ethanol, and low temperature drying followed by single action compaction. The elastic and failure properties of MMNC materials prepared using the procedure above are presented.