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- Volume 13, Issue 2, 2021
Micro and Nanosystems - Volume 13, Issue 2, 2021
Volume 13, Issue 2, 2021
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A Survey on Low Power Design Approaches in Nanoscale Regime
More LessBackground: The increased demand for battery operated portable systems boost up the field of low power VLSI design. Integrated circuits are enhancing the performance of the systems in terms of lesser area requirement, higher functionality, and faster response at lower technology nodes. The applied power supply and the threshold voltage of the individual device are scaled down at lower technology node. Scaling of the threshold voltage of the devices raises the issue of leakage current. Objective: Leakage current should be made recessive with the continuous scaling of technology nodes. Methods: Various leakage current mitigation methods had been employed to reduce the leakage current at different abstraction levels. This review paper demonstrates the survey of systematic arrangement of device scaling, leakage power, its causes, and various methods to overcome the leakage current at circuit level design. Results: 3 input NAND (NAND3) gate is designed and simulated at 22 nm technology node on HSPICE tool and analyzed for comparison of different leakage reduction techniques. Conclusion: INDEP approach is the most effective approach to reduce the leakage current and to improve the reliability of the circuits followed by DTCMOS technique as compared to other available techniques.
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Electrical and Optical Properties of CNTs Additives Chalcogenide Glasses
Authors: Priyanka Jaiswal, Pravin K. Singh, Pooja Lohia and Dilip Kumar DwivediGlasses have been used as the most versatile engineering materials for more than five decades. Chalcos is a Greek word which means ore former and glasses prepared by particular chalcogenide of group VI element of the periodic table or by their compounds have been known for more than 50 years as an optical material. The primary objective is to provide up to date description of the development in the field of optical and electrical properties of MWCNTs additive chalcogenide glasses. An extensive survey of relevant literature was carried out using sophisticated libraries, virtual media, different research laboratories, internet and also by personal contact with the senior researcher of this field. The exponential increase in D.C. conductivity was observed on increasing the CNT concentration. Inter nanotube connections increase which results in modification of chemical bond formation with increased CNT concentration. It has been observed that the optical band gap of CNT doped chalcogenide glass increases which may be attributed to the fact that CNT added to to the glasses retards the motion of charge carriers and may raise the optical bandgap. The electrical and optical properties of CNT additives chalcogenide glasses have been reviewed. Several applications based on CNT doped glasses have also been discussed, including the development of ionic memories, sensors, optical waveguides, holography, solid-state batteries, optical, and non-linear optical devices.
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Understanding the Effects of Material Properties on Nanoindentation Responses Through Data Analysis
More LessBackground: Nanoindentation is arguably the most versatile and effective method for measuring materials’ mechanical properties at nanoscale. However, due to the complexity of the deformation process during the nanoindentation tests, many experimental factors can significantly affect the nanoindentation results. Objective: This research aims to investigate the quantitative effects of material properties on nanoindentation responses and apply these relationships to the evaluation of broader material properties through nanoindentation. Methods: This study uses intensive computer modeling based on finite element analysis and modeling data analysis through curve fitting. Results: Nanoindentation responses (indentation load versus depth data) were numerically modeled by computer modeling, considering the effects of the mechanical properties of the materials (low-carbon steel AISI1018, steel alloy AISI4340, and aluminum alloy 6061-T6) and the indenter geometries (Berkovich, cylindrical, and spherical indenters). Through data analysis, the quantitative relationships between indentation load and indentation depth were established. The parameters in the formulae were optimized by the least-squares method, and high accuracy of the correlation coefficients between the modeling results and the formulae was achieved. Conclusion: It was found that the parameters of the formulae directly reflect the material properties of a testing specimen, and more material properties can be estimated through nanoindentation.
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Experimental Investigation of Microstructural Effects in Sn-Pb Solder Accumulated During Ten Years of Service Life
Authors: Marek Werner and Kerstin WeinbergAim: Solder joints of microelectronic devices are subjected to a wide range of loadings. They affect the microstructural evolution of the alloy. Long term investigations are commonly performed under thermally accelerated conditions, but are not available for real-life environmental conditions in literature yet. Therefore, the solder bumps of ten-year-old graphic cards are inspected here. Objectives: The primary objective of this study was the investigation of long-term accumulated effects in solder bumps. We classified the solder concerning its prior electrical functionality and analyzed theproperties of the microstructure. Methods: The image reconstruction is based on component identification, scratch elimination, and image stitching. Additionally, environmental scanning electron micrographs are employed to investigate the microstructure of the lead-rich phases. Results: Power supplying solder has the widest circularity distribution as a result of anisotropic diffusion and phase decomposition. On average, a bump with a cross-section of 0.12 mm2 contains 800 Pbrich phase islands. In the central region of the solder, broad Pb-rich platelets are present. Such platelets are typically perpendicular to the electric current flow and affected by the mechanical deformation of the bump. Additional electron-microscopy shows several micro-porous Pb-rich phase islands, which are induced by an uncalibrated diffusion of tin. Conclusion: We found the phase islands’ circularity to be the best indicator for the bulk dynamics. We conclude that device operation at normal working conditions leads to no hints for functional limitations at the end of the designed life span.
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Simulation for Enhancement in Sensitivity of Chalcogenide Glasses-Based Fibre Optic Evanescent Absorption Sensor for Malignant Tissue Detection
Authors: Ritesh K. Singh, Adarsh Chandra Mishra, Pooja Lohia and Dilip Kumar DwivediBackground: Refractive index determination of biological tissues is a challenging issue. Many biological species also show vibrational signature in the infrared domain. The chalcogenidebased glasses can be used to make the fibree optic evanescent wave sensors for the detection of the analyte. Objectives: The primary objective is to study the effect of various parameters on the sensitivity of chalcogenide glass-based evanescent-wave sensor for biological tissue detection. Methods: An evanescent wave sensor has been proposed with collimated source illumination and uniform tapering. The chalcogenide materials are chosen such that the weakly guiding approximation could be followed. Complex refractive indices of liver tissue samples have been taken for the analysis of sensitivity via the method of the evanescent absorption coefficient. Equations for sensitivity have been solved analytically using MATLAB software. Results: The simplification of the formula for sensitivity leads to the inference that the sensitivity is a function of core radius, refractive indices of sample tissues and wavelength used. Moreover, since the refractive indices of the materials are also a function of temperature, therefore a change in temperature results in a change in the profile of guiding mode. Hence, the effect of temperature must also be observed. The initial simulation parameters are taken; core radius 100 μm, sensing length 4 cm and wavelength 1.0 μm. In the NIR region, we have a better sensitivity of detection for all the tissue samples and the risk of photodamage of the bio-samples is reduced to a good extent. It has been found that sensitivity decreases with wavelength and core radius, whereas increases with temperature. It has also been shown that sensitivity is found to be better with collimated in comparison with the diffused source. Conclusion: The comparative study results that one should operate at a shorter NIR region of wavelength for higher sensitivity. The collimated source illumination should be preferred over diffused one for launching the light within the fibree to have high sensitivity. Further, the length of the sensing region should be larger, but the fibree core radius should be smaller. The proposed biosensor is robust and can also be used many times if the probe (sensing region) is cleaned properly. Moreover, a small amount of analyte is enough for detection. Thus, the proposed sensor is very useful for biomedical applications with its high performance, accuracy and robustness.
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Energy Efficient Configurable Layout of Logic Block in QCA Frame Work for an FPGA
Authors: Arindam Sadhu, Rimpa D. Sarkar, Kunal Das, Debashis De and Maitreyi Ray KanjilalAims: Embedded system plays a vital role in today’s life. Hence, our interest is in areadelay- energy efficient embedded system design in post-CMOS technology, i.e., QCA. Objectives: The research is focused on efficient area-delay-energy Configurable Logic Block (CLB) design for Field-Programmable Gate Array architecture (FPGA) with successful simulation-based on next-generation technology, Quantum-dot cellular automata. Methods: Each proposed circuit is designed on post CMOS 4 dot 2 electron technology, i.e. QCA (Quantum dot Cellular Automata), is adopted in circuit implementation due to low power dissipation, high clock frequency and high package density. QCADesigner is used to verify the functionality of every circuit. QCAPro tool is used for determining power dissipation. Results: In contrast, a new approach of using de-multiplexer replacing the decoder has been introduced that results in the reduction of the average energy dissipation by almost 57%. A NOR based D flip-flop memory architecture and multiplexer are also used in the lookup table for the configurable logic block. The proposed architecture thus reduces the overall latency. The proposed CLB consists of 6356 QCA cells covering 7.44 um2 area. Write and read latency of proposed CLB are 12 and 7.25 QCA clock, respectively. Conclusion: The present paper concludes that read and write latency reduction occurs; average energy dissipation, leakage, and switching energy dissipation are reduced in a large amount resulting in an advantage of the overall minimization of the latency for the proposed CLB in the process.
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Facile Template Free Shape Controlled Synthesis of α-Fe2O3 Truncated Octahedral Microstructures for the Thermal Decomposition of Ammonium Perchlorate
Authors: Vijayasree Haridas, Sankaran Sugunan and Binitha NarayananBackground: The combustion behavior of the solid rocket propellants is highly dependent on the thermal decomposition characteristics of Ammonium Perchlorate (AP) and thus low-cost, facile and scalable preparation of the additive metal oxide-based catalysts is highly desired for the decomposition of AP. Objective: A template free one-step low-cost preparation of α-Fe2O3 for its use as a catalyst in the decomposition of AP. Methods: The catalyst is prepared by the simple heating of ferric chloride at 380 °C without any chemical treatment. The material is characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and high-resolution TEM (HRTEM). The catalytic thermal decomposition of AP over α-Fe2O3 was measured by Differential Scanning Calorimetry (DSC). Results: The material exhibited a pure α-Fe2O3 crystalline phase. Morphological investigations revealed the uniform formation of truncated octahedral microstructures of α-Fe2O3. DSC analysis confirmed the two-step exothermic thermal decomposition of AP with decreased decomposition temperatures with the catalytic assistance of α-Fe2O3. Conclusion: With the catalytic assistance of low-cost and easily prepared α-Fe2O3, the decomposition temperature was decreased by 30 ºC when compared to the pure ammonium perchlorate and a high decomposition heat release of 807 Jg-1 was observed.
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Optically Controlled Superwideband to Multiband Reconfigurable Antenna for Wireless Applications
Authors: Juin Acharjee, Kaushik Mandal and Sujit K. MandalAim: Design of a reconfigurable microstrip planar antenna for wireless applications. Objective: To design an optically controlled microstrip planar antenna with superwideband (SWB) to multiband reconfigurable characteristics without using any biasing network. Methods: The use of a photoconductive switch made of Cadmium Sulphide (CDS) based semiconductor is conceived to realize the optically controlled reconfigurable antenna. The operating characteristics of the proposed antenna have been changed between SWB to multiband when the CDS coating is illuminated by the light-emitting diode. Results: Under the switch-off condition, SWB of 167% (1.8-20 GHz), fractional bandwidth with higher Bandwidth to Dimension Ratio (BDR) and a bandwidth ratio of 11.11:1 are achieved. While for the switch-on condition, triple-band (1.8-3.9 GHz, 4.3-7.3 GHz, and 8.2-15.4 GHz) operation with the resonating frequency of 3.4GHz, and 5.5GHz and, 12GHz covering the useful WiMAX, and WLAN wireless bands have been achieved with the realized peak gain of 2.34dBi, 4.18dBi, and 3.08dBi, respectively. Conclusion: An optically switchable SWB to triple-band compact planar monopole antenna has been analyzed and presented based on the simulation results. This design is reasonably compact and provides better BDR than the reported antennas of its class. The proposed design is flexible enough to adjust the operating bands by varying the dimensions of the defected ground structure (DGS) and stub. This antenna with switching ability can fulfill the requirement of the antenna society for wireless applications.
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Dapsone-Loaded Microsponge Gel for Acne Management: Preparation, Characterization and Anti-Microbial Activity
Authors: Seema Jakhar, Varsha Kadian and Rekha RaoBackground: Acne vulgaris is a chronic inflammatory disorder involving Propionibacterium acnes and activation of lymphocytes and neutrophils. Dapsone (sulfone drug) possesses potent anti-microbial activities and hence, it is used to cure multiple inflamed acne lesions. Howbeit, its therapeutic utility is hampered, owing to its poor solubility and side effects like mild irritation and dryness. These problems, along with orange-brown discoloration on skin, restrict the topical application of this drug. Objective: The objective of the present investigation was to address the above-mentioned limitations like irritation, dryness, and skin discoloration of dapsone via formulating microsponge based gel of this moiety. Methods: Dapsone microsponges were fabricated and embedded into a carbopol gel for topical application. The drug loaded ethylcellulose microsponges were crafted employing a quasi emulsion solvent diffusion technique. Besides routine characterization, these microformulations were assessed for entrapment, particle size analysis, and drug release. Furthermore, anti-acne potential was also evaluated against Propionibacterium acnes and Staphylococcus aureus to check their therapeutic efficiency. The prepared dapsone microsponge gel was assessed for its viscosity, spreadability, texture, and drug release. Results: Results revealed that dapsone loaded microsponges were successfully fabricated and found to possess good encapsulation efficiency (84.68 ± 5.73%), which is in micro-size range (88.06 ± 2.97 μm to 315.87 ± 1.99 μm) and showed cumulative drug release of 52.52 ± 0.2%. Field emission scanning electron microscopy illustrated spherical, uniform, and spongy microparticles. The developed micro formulation showed promising activity against the chosen acne bacterias and improved stability. Conclusion: The obtained results corroborate the premise that dapsone loaded microsponge gel can be an effective strategy for acne management.
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A New Keeper Domino Logic Based Full Adder for High-Speed Arithmetic Circuits
Authors: Deepika Bansal, Bal C. Nagar, Brahamdeo Prasad Singh and Ajay KumarObjective: A new efficient keeper circuit has been proposed in this article for achieving low leakage power consumption and to improve the power delay product of the dynamic logic using carbon nanotube MOSFET. Methods: As a benchmark, a one-bit adder has been designed and characterized with both technologies Si-MOSFET and CN-MOSFET using proposed and existing dynamic circuits. Furthermore, a comparison has been made to demonstrate the superiority of CN-MOSFET technology with Synopsys HSPICE tool for multiple bit adders available in the literature. Results: The simulation results show that the proposed keeper circuit provides lower static and dynamic power consumption up to 57 and 40%, respectively, as compared to the domino circuits using 32nm CN-MOSFET technology provided by Stanford University. Moreover, the proposed keeper configuration provides better performance using Si-MOSFET and CN-MOSFET technologies. Conclusion: A comparison of the proposed keeper with previously published designs is also given in terms of power consumption, delay and power delay product with the improvement up to 75, 18 and 50%, respectively. The proposed circuit uses only two transistors, so it requires less area and gives high efficiency.
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Multipliers Based on Approximate Compressors
More LessBackground: Approximate computing is an emerging trend in recent years that trades off the requirement of exact computation for the improvement of speed and power performance. Objective: Researchers are trying to improve the speed and power performance proposing different algorithms. Methods: This paper proposes approximate compressors used for the design of approximate multipliers. Results: By using the proposed method, approximate multipliers of different length have been synthesized and a comparative study with previously presented multipliers have been dealt here which shows that the proposed circuits have better speed and power. Conclusion: Finally, the proposed circuits have been used for image processing applications.
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