Amirkabir University of Technology

About: Amirkabir University of Technology is a education organization based out in Tehran, Iran. It is known for research contribution in the topics: Nonlinear system & Finite element method. The organization has 15254 authors who have published 31165 publications receiving 487551 citations. The organization is also known as: Tehran Polytechnic & Tehran Polytechnic University.

Breaking through barriers to TQM effectiveness: Lack of commitment of upper-level management

Abstract: This paper examines the importance of senior management commitment to successful implementation of TQM initiatives. Subsumed under the general heading of senior management commitment will be the issues of employee commitment and, in consequence, the TQM success. The interrelationship between CEO commitment, employee commitment and effectiveness of TQM programmes is usually a very close and linear one, not least because, if a TQM organization wishes to improve and achieve success it has no choice but to be committed fully from top to shop floor. As commitment of senior management and employees are not substitutable, it is difficult to study either issue in isolation. The paper opens with an attempt to offer a clear explanation of TQM practices, and goes on from this to outline the importance of a highly-committed CEO and his or her senior management team as a test of whether an organization considers TQM initiatives as a managerial panacea towards competitive advantage or just another management f...

Electrospun nanofibers comprising of silk fibroin/gelatin for drug delivery applications: Thyme essential oil and doxycycline monohydrate release study.

Abstract: In this study, a nanofibrous electrospun substrate based on the silk fibroin (SF) and gelatin (GT) polymers were prepared and evaluated. The SF/GT blended solutions were prepared with various ratios of GT in formic acid and electrospun to obtain bead-free fibers. Results showed that addition of GT to SF increased nanofiber's diameter, bulk hydrophilicity, surface wettability, mass loss percentage, but decreased Young's modulus, tensile strength, and porosity of the SF/GT mats. According to the obtained results, the mat containing 10% of GT was selected as the optimized mat for further studies and loaded with thyme essential oil (TEO) and doxycycline monohydrate (DCMH) as the antibacterial agents. Release studies showed a burst release of TEO from the mat within the first 3 h, while the DCMH had a sustained release during 48 h. In comparison to the TEO-loaded mat, the DCMH-loaded one showed larger inhibition zones against Staphylococcus aureus and Klebsiella pneumoniae bacteria. Meanwhile, cellular studies using mouse fibroblast L929 cells showed excellent cell-compatibility of TEO- and DCMH-loaded mats. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1092-1103, 2018.

Improving Fault Ride-Through Capability of Fixed-Speed Wind Turbine by Using Bridge-Type Fault Current Limiter

Abstract: The interaction between wind turbines and grid results in increasing short-circuit level and fault ride-through (FRT) capability problem during fault condition. In this paper, the bridge-type fault current limiter (FCL) with discharging resistor is used for solving these problems. For this FCL, a control scheme is proposed, which uses the dc reactor current as control variable, to adjust the terminal voltage of induction generator (IG) without measuring any parameters of system. In this paper, the wind energy conversion system (WECS) is a fixed-speed system equipped with a squirrel-cage IG. The drivetrain is represented by a two-mass model. The analytical and simulation studies of the bridge-type FCL and proposed control scheme for limiting the fault current and improving FRT capability are presented and compared with the impact of the application of the series dynamic braking resistor (SDBR).

Engineering Properties of Alkali-Activated Natural Pozzolan Concrete

Abstract: The development of alkali-activated binders with superior engineering properties and longer durability has emerged as an alternative to ordinary portland cement (OPC) It is possible to use alkali-activated natural pozzolans to prepare environmentally friendly geopolymer cement leading to the concept of sustainable development This paper presents a summary of an experimental work that was conducted to determine mechanical strength, modulus of elasticity, ultrasonic pulse velocity, and shrinkage of different concrete mixtures prepared with alkali-activated Iranian natural pozzolans—namely Taftan andesite and Shahindej dacite, both with and without calcining Test data were used for Taftan pozzolan to identify the effects of water-binder ratios (w/b) and curing conditions on the properties of the geopolymer concrete, whereas the influence of material composition was studied by activating Shahindej pozzolan both in the natural and calcined states The results show that alkali-activated natural pozzolan (AANP) concretes develop moderate-to-high mechanical strength with a high modulus of elasticity and a shrinkage much lower than with OPC

A fractional-order model for the novel coronavirus (COVID-19) outbreak.

Abstract: The outbreak of the novel coronavirus (COVID-19), which was firstly reported in China, has affected many countries worldwide To understand and predict the transmission dynamics of this disease, mathematical models can be very effective It has been shown that the fractional order is related to the memory effects, which seems to be more effective for modeling the epidemic diseases Motivated by this, in this paper, we propose fractional-order susceptible individuals, asymptomatic infected, symptomatic infected, recovered, and deceased (SEIRD) model for the spread of COVID-19 We consider both classical and fractional-order models and estimate the parameters by using the real data of Italy, reported by the World Health Organization The results show that the fractional-order model has less root-mean-square error than the classical one Finally, the prediction ability of both of the integer- and fractional-order models is evaluated by using a test data set The results show that the fractional model provides a closer forecast to the real data