Carbon fiber reinforced aluminum laminates (CARALL) are one of the aluminum based Fiber metal laminates (FMLs) which, due to their high strength to weight ratio and good impact resistance are greatly replacing aluminum alloys in aircraft structures. In this research work, interlaminate shear strength of Vacuum assisted resin transfer molding (VARTM) manufactured CARALL has been investigated. Numerical simulation model incorporated with real time material data has been developed to predict the delamination behavior of CARALL laminates. Standard CARALL specimens with different surface morphologies were prepared by electric discharge machining, mechanical, chemical and electrochemical surface treatments. T-peel tests were carried out according to standard ASTM D1876-08 to find out inter laminate shear strength. FMLs made out of mechanically, chemically and electrochemically cleaned metal sheets depicted high interlaminate shear strength. SEM micrographs of failed surfaces verify the high adhesive strength of epoxy. Developed numerical simulation model accurately predicts the delamination behavior of CARALL as observed during experimentation. 相似文献
In high-pressure die casting, cooling time greatly affects the total cycle time. As thermal conductivity is the main governing factor, a higher thermal conductive die material allows faster extraction of heat from the casting, thus resulting in shorter cycle time and higher productivity. This paper presents a novel approach to replace a conventional steel die by a bimetallic die made of Moldmax copper alloy coated with a protective layer of steel using laser cladding technology, direct metal deposition on the cavity surface for high-pressure die casting of aluminum alloys. Study includes the investigation of suitable steel layer thickness on Moldmax substrate in terms of porosity, hardness, presence of copper content, and copper particle. Results obtained from the scanning electron microscope and energy dispersive spectroscopy display a metallurgicallly sound and fully dense steel layer on copper alloy. Results of finite element heat transfer analysis also show that bimetallic die offers superior thermal performance compared with monolithic steel die. 相似文献
Due to limited depth-of-field of digital single-lens reflex cameras, the scene content within a limited distance from the imaging plane remains in focus while other objects closer to or further away from the point of focus appear as blurred (out-of-focus) in the image. Multi-Focus Image Fusion can be used to reconstruct a fully focused image from two or more partially focused images of the same scene. In this paper, a new Fuzzy Based Hybrid Focus Measure (FBHFM) for multi-focus image fusion has been proposed. Optimal block size is very critical step for multi-focus image fusion. Particle Swarm Optimization (PSO) algorithm has been used to find optimal size of the block of the images for extraction of focus measure features. After finding optimal blocks, three focus measures Sum of Modified Laplacian, Gray Level Variance and Contrast Visibility has been extracted and combined these focus measures by using intelligent fuzzy technique. Fuzzy based hybrid intelligent focus values were estimated using contrast visibility measure to generate focused image. Different sets of multi-focus images have been used in detailed experimentation and compared the results with state-of-the-art existing techniques such as Genetic Algorithm (GA), Principal Component Analysis (PCA), Laplacian Pyramid discrete wavelet transform (DWT), and aDWT for image fusion. It has been found that proposed method performs well as compare to existing methods.
Thermal oils are widely used as heat transfer fluids in medium temperature applications. Addition of small amounts of nanoparticles in such fluids can significantly improve their thermophysical properties. This paper presents experimental investigation of an oil‐based nanofluids prepared by dispersing different concentrations (0.25 wt%–1.0 wt%) of copper oxide nanoparticles in Therminol‐55 oil using two‐step method. Shear mixing and ultrasonication were used for uniform distribution and de‐agglomeration of nanoparticles to enhance the stability of the suspensions. The effect of nanoparticles concentrations on thermophysical properties of the nanofluids was analysed by measuring thermal conductivity, dynamic viscosity, effective density and specific heat capacity at different temperatures (25 °C–130 °C). Thermal conductivity exhibited increasing trend with rising temperature and increase in nanoparticles loading. A significant decrease in dynamic viscosity and effective density against increasing temperature makes it suitable for medium temperature applications. Nano‐oils with improved thermal properties are expected to increase the efficiency of concentrating solar thermal collectors. 相似文献
Biomechanics is the study of physiological properties of data and the measurement of human behavior. In normal conditions, behavioural properties in stable form are created using various inputs of subconscious/conscious human activities such as speech style, body movements in walking patterns, writing style and voice tunes. One cannot perform any change in these inputs that make results reliable and increase the accuracy. The aim of our study is to perform a comparative analysis between the marker-based motion capturing system (MBMCS) and the marker-less motion capturing system (MLMCS) using the lower body joint angles of human gait patterns. In both the MLMCS and MBMCS, we collected trajectories of all the participants and performed joint angle computation to identify a person and recognize an activity (walk and running). Using five state of the art machine learning algorithms, we obtained 44.6% and 64.3% accuracy in person identification using MBMCS and MLMCS respectively with an ensemble algorithm (two angles as features). In the second set of experiments, we used six machine learning algorithms to obtain 65.9% accuracy with the k-nearest neighbor (KNN) algorithm (two angles as features) and 74.6% accuracy with an ensemble algorithm. Also, by increasing features (6 angles), we obtained higher accuracy of 99.3% in MBMCS for person recognition and 98.1% accuracy in MBMCS for activity recognition using the KNN algorithm. MBMCS is computationally expensive and if we re-design the model of OpenPose with more body joint points and employ more features, MLMCS (low-cost system) can be an effective approach for video data analysis in a person identification and activity recognition process. 相似文献
We performed ab initio calculations using the FPLAW method with the local density approximation (LDA) implemented in the WIEN2 k code for the orthorhombic (α) and triclinic (β) phases of BiNbO4. The modified Becke–Johnson exchange potential (mBJ)-LDA approach was also used to improve the electronic properties. The lattice constants calculated for both structures using the LDA are in good agreement with the experimental values. For the band structure calculations, the mBJ-LDA approach provides reasonable agreement for the band gap value compared with the LDA. The estimated (mBJ)-LDA band gap values are 2.89 eV (3.73 eV) and 2.62 eV (3.15 eV) for the α and β phases of BiNbO4, respectively. Significant optical anisotropy is clearly observed in the visible-light region. We also calculated and evaluated the electron energy loss spectrum for BiNbO4. This work provides the first quantitative theoretical prediction of optical properties and electron energy loss spectra for both the orthorhombic and triclinic phases of BiNbO4. 相似文献