Experimental Investigations of Process Parameters Influence on Rheological Behavior and Dynamic Mechanical Properties of FDM Manufactured Parts

Fused deposition modeling (FDM) has gained popularity in industry because of its ability to manufacture complex parts. But when it comes to the manufacturing of functional products, the advantages of FDM are not so distinct due to the high number of intervening parameters and complex optimal settings setup. This paper investigates the influence of process parameters on the rheological and dynamic mechanical properties of FDM-manufactured parts. In this study, an attempt has been made to establish an empirical relationship between the FDM input parameters and the properties involved using IV-optimal response surface methodology and statistical analysis. Further, optimized process parameters were established to maximize the rheological and dynamic mechanical properties through the graphical optimization. The optimization results show that the parameters with the most significant effect on the rheological and dynamic mechanical properties are the layer thickness, the air gap, the road width, and the number of contours. The results also show that by taking into consideration the number of contours, the functionality of manufactured part is improved significantly.     

Tuning of the swelling and dye removal efficacy of poly(acrylamide-AMPS)-based smart hydrogel

Hydrogels responsive to pH change based on poly(acrylamide-co-2-acrylamido-2-methylpropane sulfonic acid) are synthesized. The hydrogels are characterized in terms of FTIR spectroscopy, swelling–deswelling behavior, morphological analysis and dye removal properties. The swelling of the hydrogel is strongly dependent on the copolymer composition, pH and ionic strength of the medium. The dye removal efficiency (DRE) also depends on the copolymer composition, pH and ionic strength. Pseudo-second-order kinetics and Langmuir isotherms model, respectively, are the best-fit models for the present gel. The cellular structures of the hydrogels are clearly revealed by optical microscopic and SEM images.     

Microstructure Development,Wear Characteristics and Kinetics of Thermal Decomposition of Hybrid Nanocomposites Based on Poly Aryl Ether Ketone,Boron Carbide and Multi Walled Carbon Nanotubes

In the present study a high performance polymer poly aryl ether ketone (PAEK) is reinforced with micro and nano boron carbide (B₄C) and functionalized multi walled carbon nanotubes (F-MWCNT) to investigate the individual and hybrid effect of the fillers. Optical microscopy and transmission electron microscopy suggested the dispersion of micro and nano fillers respectively in PAEK matrix. The inclusion of B₄C nano fillers increased the hardness of the composites which aided the wear resistance of the composites. The morphological features of the worn surface of the samples are analyzed using scanning electron microscopy. It is found from the izod impact test analysis that the impact strength of the composite enhanced by the F-MWCNT inclusion. The thermal properties of PAEK in the composites are studied using differential scanning calorimetry and it revealed dominant effect of F-MWCNT influencing the thermal transitions than the B₄C particles. The kinetics of thermal degradation of various composites is analyzed using Coats–Redfern method. The positive influence of B₄C in the matrix indicates that the thermal degradation is delayed due to the higher activation energy it possesses. The overall results shows that the hybrid nanocomposite exhibits better properties compared to individual micro and nano composites.     

Fractal dimension of synthesized and natural color images in Lab space

Pattern Analysis and Applications - Fractal dimension (FD) is a useful metric for the analysis of natural images that exhibit a high degree of complexity, randomness and irregularity in color and...     

SVM-based hierarchical architectures for handwritten Bangla character recognition

We propose support vector machine (SVM) based hierarchical classification schemes for recognition of handwritten Bangla characters. A comparative study is made among multilayer perceptron, radial basis function network and SVM classifier for this 45 class recognition problem. SVM classifier is found to outperform the other classifiers. A fusion scheme using the three classifiers is proposed which is marginally better than SVM classifier. It is observed that there are groups of characters having similar shapes. These groups are determined in two different ways on the basis of the confusion matrix obtained from SVM classifier. In the former, the groups are disjoint while they are overlapped in the latter. Another grouping scheme is proposed based on the confusion matrix obtained from neural gas algorithm. Groups are disjoint here. Three different two-stage hierarchical learning architectures (HLAs) are proposed using the three grouping schemes. An unknown character image is classified into a group in the first stage. The second stage recognizes the class within this group. Performances of the HLA schemes are found to be better than single stage classification schemes. The HLA scheme with overlapped groups outperforms the other two HLA schemes.     

Comparison of organic and inorganic alignment layers for low‐power liquid‐crystal devices using low‐frequency applied‐voltage waveforms

Abstract— Bistable displays are known to have low‐power consumption, but they usually lack the ability to display full‐color video‐rate images. Operating active‐matrix liquid‐crystal displays (AMLCDs) with an ultra‐wide refresh‐rate range, down to ～1 Hz, can lower the power consumption to that of bistable devices and offer video rates as well. A SiO^x‐layer‐based liquid‐crystal (LC) alignment technique is studied here to overcome the ion problems typically encountered with low‐refresh‐rate devices. The effect of ions on the voltage‐holding ratio (VHR) and residual DC voltage (RDC) with SiO^x‐based LC alignment is compared with those for polyimide‐based LC alignment. It is found that only SiO^x alignment provides high VHR and small RDC, with good stability over time. Therefore, it is shown that SiO^x alignment is an excellent candidate for low‐power AMLCDs operated with an ultra‐wide refresh‐rate range.     

Design and power analysis of 4 × 4 semiconductor ROM array with row decoder and column decoder at 32, 22 and 16 nm channel length of MOS transistor

Microsystem Technologies - In this work, the design and power consumption analysis of NOR based 4 × 4 semiconductor read-only-memory (ROM) array has been presented. In this...