Nanoarchitectonics of nanoporous carbon materials (NCMs) derived from natural resource; Areca Catechu Nut (ACN) with enhanced electrochemical supercapacitance properties is reported. ACN powder is chemically activated in a tubular furnace at 400?°C and the effect of activating agent sodium hydroxide (NaOH), zinc chloride (ZnCl2) and phosphoric acid (H3PO4) on the textural properties, surface functional groups and electrochemical supercapacitance properties was thoroughly examined. We found that ACN derived NCMs are amorphous in nature comprising of macropores, micropores and hierarchical micro- and mesopore architecture depending on the activating agent. Surface area and pore volume are found in the range 25–1985 m2 g?1 and 0.12–3.42 cm3 g?1, respectively giving the best textural properties for H3PO4 activated NCM. Nevertheless, despite the different chemical activating agent used, all the prepared NCMs showed similar oxygen-containing surface functional groups (carboxyl, carboxylate, carbonyl and phenolic groups). The H3PO4 activated NCM showed excellent supercapacitance properties giving a high specific capacitance of ca. 342 F g?1 at a scan rate of 5 mV s?1 together with the high cyclic stability sustaining capacitance retention of about 97% after 5000 charging/discharging cycles. Electrochemical supercapacitance properties have demonstrated that the ACN derived novel nanoporous carbon material would be a potential material in energy storage application. 相似文献
In this paper, an asymmetric hybrid cryptosystem utilizing four-dimensional (4D) hyperchaotic framework by means of coherent superposition and random decomposition in hybrid multi-resolution wavelet domain is put forward. The 4D hyperchaotic framework is utilized for creating permutation keystream for a pixel swapping procedure. The hybrid multi-resolution wavelet is formed by combining Walsh transform and fractional Fourier transform of various orders. The 4D hyperchaotic framework’s parameters and preliminary conditions alongside the fractional orders extend the key-space and consequently give additional strength to the proposed cryptosystem. The proposed cryptosystem has an extended key-space to avoid any brute-force attack and is nonlinear in nature. The scheme is validated on greyscale images. Computer-based simulations have been executed to validate the robustness of the proposed scheme against different types of attacks. Results demonstrate that the proposed cryptosystem along with offering higher protection against noise and occlusion attacks is also unassailable to special attack.
The modern wireless communication system requires high performance portable devices, thus designing of such communicating devices plays a major role. More particularly, meander shape is selected over the traditional shapes of microstrip patch antenna for the application of portable device antenna. Accordingly, in this paper, orthogonal meander architecture along with PIN diodes are proposed to achieve vertical and horizontal polarization. Further, to control switching of PIN diodes, Raspberry PI system is employed. In the proposed method, a novel meander-shaped antenna is designed and simulated using High-Frequency Structure Simulator-11 (HFSS-11) with an operating frequency of 2.4 GHz. However, the optimized design dimensions are used to fabricate the antenna and then the results are verified. This paper highlights the simulated and experimental results including, S-Parameter, radiation pattern, current distribution, co and cross polarization, path loss and impedance. Besides, the paper demonstrates the effect of cover on the antenna performance. Finally, the proposed meander shape reconfigurable antenna have validated as a portable device antenna from the obtained results for wireless communication applications.
Side-channel attacks pose an inevitable challenge to the implementation of cryptographic algorithms, and it is important to mitigate them. This work identifies a novel data encoding technique based on 1-of-4 codes to resist differential power analysis attacks, which is the most investigated category of side-channel attacks. The four code words of the 1-of-4 codes, namely (0001, 0010, 1000, and 0100), are split into two sets: set-0 and set-1. Using a select signal, the data processed in hardware is switched between the two encoding sets alternately such that the Hamming weight and Hamming distance are equalized. As a case study, the proposed technique is validated for the NIST standard AES-128 cipher. The proposed technique resists differential power analysis performed using statistical methods, namely correlation, mutual information, difference of means, and Welch's t-test based on the Hamming weight and distance models. The experimental results show that the proposed countermeasure has an area overhead of 2.3× with no performance degradation comparatively. 相似文献
In the past few decades, Energy Efficiency (EE) has been a significant challenge
in Wireless Sensor Networks (WSNs). WSN requires reduced transmission delay and
higher throughput with high quality services, it further pays much attention in increased
energy consumption to improve the network lifetime. To collect and transmit data
Clustering based routing algorithm is considered as an effective way. Cluster Head (CH)
acts as an essential role in network connectivity and perform data transmission and data
aggregation, where the energy consumption is superior to non-CH nodes. Conventional
clustering approaches attempts to cluster nodes of same size. Moreover, owing to randomly
distributed node distribution, a cluster with equal nodes is not an obvious possibility to
reduce the energy consumption. To resolve this issue, this paper provides a novel,
Balanced-Imbalanced Cluster Algorithm (B-IBCA) with a Stabilized Boltzmann Approach
(SBA) that attempts to balance the energy dissipation across uneven clusters in WSNs. BIBCA utilizes stabilizing logic to maintain the consistency of energy consumption among
sensor nodes’. So as to handle the changing topological characteristics of sensor nodes, this
stability based Boltzmann estimation algorithm allocates proper radius amongst the sensor
nodes. The simulation shows that the proposed B-IBCA outperforms effectually over other
approaches in terms of energy efficiency, lifetime, network stability, average residual
energy and so on. 相似文献
The formation of acrylamide in papads processed by flame roasting, frying and microwave roasting as a function of the alkaline salt, papad khar and its substitute, 2:1 sodium carbonate:sodium bicarbonate (w/w) at various concentrations was examined. Addition of papad khar and 2:1 sodium carbonate:sodium bicarbonate makes the product alkaline, which is known to be conducive for the formation of acrylamide. While a correlation was found between acrylamide content and pH with respect to fried and flame roasted papads, microwave roasting did not show any acrylamide formation at all the levels of alkaline salts tested in this study. Flame roasting generated higher levels of acrylamide as compared to frying. Use of microwave roasting is therefore recommended as a consumer-friendly, healthy and safe technology for processing papads. 相似文献
The Himalaya has a rich ancient tradition for tapping hydro-energy from the hill streams and rivers through the device of gharats (watermills). The present contribution encompasses the study on the energy consumption pattern of hill communities living in buffer zone of the Nanda Devi Biosphere Reserve, a world heritage site located in Garhwal Himalayas, India, The current status of gharats, the factors responsible for the neglect of this renewable energy device, initiatives taken for upgrading for their revival have been highlighted. Field and policy level opportunities and constraints associated with promotion of such hydro-energy in the study area by upgrading of traditional watermills are analysed and suitable options for removing impediments are suggested. 相似文献