ABSTRACT
Smart farming, as a branch of the Internet of Things (IoT), combines the recognition of agricultural economic competencies and the progress of data and information collected from connected devices with statistical analysis to characterize the essentials of the assimilated information, allowing farmers to make intelligent conclusions that will maximize the harvest benefit. However, the integration of advanced technologies requires the adoption of high-tech security approaches. In this paper, we present a framework that promises to enhance the security and privacy of smart farms by leveraging the decentralized nature of blockchain technology. The framework stores and manages data acquired from IoT devices installed in smart farms using a distributed ledger architecture, which provides secure and tamper-proof data storage and ensures the integrity and validity of the data. The study uses the AWS cloud, ESP32, the smart farm security monitoring framework, and the Ethereum Rinkeby smart contract mechanism, which enables the automated execution of pre-defined rules and regulations. As a result of a proof-of-concept implementation, the system can detect and respond to security threats in real time, and the results illustrate its usefulness in improving the security of smart farms. The number of accepted blockchain transactions on smart farming requests fell from 189,000 to 109,450 after carrying out the first three tests while the next three testing phases showed a rise in the number of blockchain transactions accepted on smart farming requests from 176,000 to 290,786. We further observed that the lesser the time taken to induce the device alarm, the higher the number of blockchain transactions accepted on smart farming requests, which demonstrates the efficacy of blockchain-based poisoning attack mitigation in smart farming.
ABSTRACT
This study successfully deposited Si-doped CrN coatings onto Si (100) substrate by direct current magnetron sputtering. The concentration of Si in the CrSiN coatings was varied by changing the Si target current during deposition. The microstructural and mechanical properties were determined by employing X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy, and nanoindentation test. According to the results, the coating with 3.3 at.% Si contents (CrSiN-2) show an increase and decrease in the crystallite size and coating surface roughness, respectively, leading to solid solution hardening with an optimum hardness and elastic modulus of 21.37 GPa and 205.68 GPa, respectively. With continued Si addition, the coating roughness increased and the mechanical properties gradually decreased and attained 184.08 GPa and 18.95 GPa for the elastic modulus and hardness of the coating with a maximum Si concentration of 9.2 at.% (CrSiN-5).
ABSTRACT
The dependency of adsorption behaviour on the aspect ratio of multi-walled carbon nanotubes (MWCNTs) has been explored. In this study, effect of growth temperature on yield and aspect ratio of MWCNTs by catalytic chemical vapour deposition (CCVD) method is reported. The result revealed that yield and aspect ratio of synthesised MWCNTs strongly depend on the growth temperature during CCVD operation. The resulting MWCNTs were characterized by High Resolution Transmission Electron Microscope (HRTEM), Dynamic Light Scattering (DLS) and X-ray diffraction (XRD) techniques to determine it diameter, hydrodynamic diameter and crystallinity respectively. Aspect ratio and length of the grown MWCNTs were determined from the HRTEM images with the hydrodynamic diameter using the modified Navier-Stokes and Stokes-Einstein equations. The effect of the prepared MWCNTs dosage were investigated on the Turbidity, Iron (Fe) and Lead (Pb) removal efficiency of coal washery effluent. The MWCNTs with higher length (58.17 µm) and diameter (71 nm) tend to show high turbidity and Fe removal, while MWCNTs with lower length (38.87 µm) and diameter (45 nm) tend to show high removal of Pb. Hence, the growth temperature during CCVD operation shows a great effluence on the aspect ratio of MWCNTs which determines it area of applications.
