Implementation of RUL Estimation Approaches on Software Platform, Concentrated on Confidence Level Determination in Rolling Element Bearings

, M.Sc. Thesis Sharif University of Technology Mirfarah, Motahareh (Author) ; Behzad, Mehdi (Supervisor)

Abstract

Estimating the remaining useful life (RUL) of critical assets is an essential task in system health management. It also has a crucial role in the optimization of maintenance scheduling and decision making about the future of the asset. On the other hand, since the rolling element bearings are widely used in the rotating machinery, estimation of their RUL is considered as remarkable progress in improving the reliability of the whole system. In this way, various models have been introduced to predict the RUL of rolling element bearings, which their proper functionality is affected by the underlying assumptions in the model structure. Because of the presence of several uncertainties and...

A new methodology to deal with the multi-phase degradation in rolling element bearing prognostics

, Article Smart Innovation, Systems and Technologies, 3 September 2019 through 5 September 2019 ; Volume 166 , 2020 , Pages 855-869 Mollaali, A ; Behzad, M ; Mirfarah, M ; Sharif University of Technology

Springer Science and Business Media Deutschland GmbH 2020

Abstract

Predicting the residual-life (RL) of rolling element bearings (REBs) is an essential procedure of rotating machinery condition monitoring, in industries. Since the bearing fault propagation has a complicated stochastic nature, the multi-phase phenomenon is probable to happen in the degradation process. By occurrence of the multi-phase phenomenon, the degradation process experiences different phases, with distinct failure rate in each phase. Therefore, the mentioned phenomenon leads to large error in the prediction results of single-phase degradation models. The main concern of the present paper is to consider the effect of multi-phase phenomenon on the prediction confidence level of REBs. In...

Relativistic Magnetohydrodynamics of a Spinful and Vortical Fluid: Entropy Current Analysis and Transport Coefficients

, M.Sc. Thesis Sharif University of Technology Seⅾighi Jafari, Ⅿahⅾi (Author) ; Sadooghi, Neda (Supervisor) ; Kiamari, Motahareh (Co-Supervisor)

Abstract

Fluid Mechanics can be considered as an effective method for studying many-body effects in classical and quantum systems. In recent years, relativistic hydrodynamics has found different applications in different branches of physics. One of these applications is the quantitative description of the experimental behavior of relativistic heavy-ion collisions. More specifically, studying fluid mechanics in the presence of magnetic fields (magnetohydrodynamics) and vorticity is of great importance in heavy-ion collision experiments. In this framework, on the one hand, the interaction between spin and magnetic field, and on the other hand, the interaction between spin and angular momentum of the...

Preparation a Polymeric Membrane for Dehydration of Acetic Acid

, M.Sc. Thesis Sharif University of Technology Mirfarah, Hesam (Author) ; Mousavi, Abbas (Supervisor) ; Bastani, Dariush (Supervisor)

Abstract

The separation ofacetic acids in binary water solutions hasbeenstudied using a reverse osmosis (RO) membrane. Thin film composite polyamide membrane is used in this study.Thin-film composite (TFC) membrane was prepared through the interfacial polymerization between m-phenylenediamine (MPD) and trimesoyl chloride (TMC) on the polysulphone support membrane.The solute permeation was carried out under applied pressure of 5 bar at 25°C. In this work the effect of various synthesis conditions on the membrane performance was investigated. Parametric studies were conducted by varyingconcentration of reactants, reaction time, curing time and curing temperature. By suitable combination of these...

Synthesis and characterization of polyamide membrane for the separation of acetic acid from water using RO process

, Article Membrane Water Treatment ; Volume 8, Issue 4 , 2017 , Pages 323-336 ; 20058624 (ISSN) Mirfarah, H ; Mousavi, S. A ; Mortazavi, S. S ; Sadeghi, M ; Bastani, D ; Sharif University of Technology

Techno Press 2017

Abstract

The main challenge in many applications of acetic acid is acid dehydration and its recovery from wastewater streams. Therefore, the performance of polyamide thin film composite is evaluated to separate acetic acid from water. To reach this goal, the formation of polyamide layer on polysulfone support membrane was investigated via interfacial polymerization (IP) of meta-phenylenediamine (MPD) in water with trimesoyl chloride (TMC) in hexane. Also, the effect of synthesis conditions, such as concentration of monomers and curing temperature on separation of acetic acid from water were investigated by reverse osmosis process. Moreover, the separation mechanism was discussed. The solute...