Comparison of theories of anisotropy in transformer oil-based magnetic fluids

The external magnetic field in transformer oil-based magnetic fluids leads to the aggregation of magnetic nanoparticles and formation of clusters. These aggregations are the result of the interaction between the external magnetic field and the magnetic moments of the nanoparticles occurs. However, the temperature of magnetic fluids has also very important influence on the structural changes because the mechanism of thermal motion acts against the cluster creation. The acoustic spectroscopy was used to study the anisotropy of transformer oil-based magnetic fluids upon the effect of an external magnetic field and temperature. In present the anisotropy of the magnetic fluids can be described by two theories. Taketomi theory assumes the existence of spherical clusters. These clusters form long chains, aligned in a magnetic field direction. Shliomis in his theory supposed that only nanoparticles formed chains. A comparison of the experimental results with the predictions of the Taketomi theory allowed a determination of the cluster radius and the number density of the colloidal particles. The proportions of the acoustic wave energy used for excitation of the translational and rotational motion were determined

Detecting and Preventing Credential Misuse in OTP-Based Two and Half Factor Authentication Toward Centralized Services Utilizing Blockchain-Based Identity Management

This work focuses on the problem of detection and prevention of stolen and misused secrets (such as private keys) for authentication toward centralized services. We propose a solution for such a problem based on the blockchain-based two-factor authentication scheme SmartOTPs, which we modify for our purposes and utilize in the setting of two and half-factor authentication against a centralized service provider. Our proposed solution consists of four entities that interact together to ensure authentication: (1) the user, (2) the authenticator, (3) the service provider, and (4) the smart contract. Out of two and a half factors of our solution, the first factor stands for the private key, and the second and a half factor stands for one-time passwords (OTPs) and their precursors, where OTPs are obtained from the precursors (a.k.a., pre-images) by cryptographically secure hashing. We describe the protocol for bootstrapping our approach as well as the authentication procedure. We make the security analysis of our solution, where on top of the main attacker model that steals secrets from the client, we analyze man-in-the-middle attacks and malware tampering with the client. In the case of stolen credentials, we show that our solution enables the user to immediately detect the attack occurrence and proceed to re-initialization with fresh credentials

Design of the Discharging Electrode of the Electrostatic Precipitator Depending on the Applied Voltage

The article deals with the design of the diameter and the simulation of the distribution of the intensity of the electric field of the charging electrode of the electrostatic precipitator, given the supplied DC voltage. The purpose was to calculate the value of the critical intensity of the electric field, which must be exceeded when trying to achieve the state of corona discharge on the electrode, which is a condition for electrostatic separation. Subsequently, CFD simulations of two 3D models with electrode diameters of 1 and 4 mm were created, on which the distributions of the electric field intensity were observed at a DC voltage of 20 kV. The simulations confirmed the results of the calculations that the corona discharge at a voltage of 20 kV will occur only on an electrode with a diameter of 1 mm

Pyrolysis Treatment of Municipal Solid Waste and Automotive Waste with Study of Each Component Energy Potential

Many research is aimed at improving municipal solid waste disposal and producing usable energy. Pyrolysis technology not only decreases the volume of municipal solid waste, but it also produces pyrolysis oil, pyrolysis gas, and carbon, all of which have a high calorific value and are widely used in industrial activities. This article focuses on the plant-based pyrolysis of municipal solid waste and automotive plastic trash. The research also discusses the pyrolysis energy potential of municipal solid waste components such as plastics, biomass, rubber, and plastics. The energy potential of plastic waste from vehicle components was also investigated in this study, which used thermogravimetric and elemental analysers. According to the findings of the examination of the most common plastic waste from automobiles, it is possible to determine the potential treatment of this waste by pyrolysis. By analyse municipal solid waste, it was discovered that waste treatment by pyrolysis might lower the environmental load in Slovakia in the future, ensuring a greater quality of life, inexpensive and sustainable energy for humanity, and strengthening waste treatment innovation