Iran University of Science and Technology

About: Iran University of Science and 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 12917 authors who have published 24965 publications receiving 372013 citations. The organization is also known as: Governmental Technical Institute & Advanced Art College.

A batch-fabricated silicon thermopile infrared detector

Abstract: A thermopile infrared detector fabricated using silicon integrated-circuit technology is described. The device uses a series-connected array of thermocouples whose hot junctions are supported an a thin silicon membrane formed using anisotropic etching and a diffused boron etch stop. The membrane size and thickness control the speed and responsivity of the structure, which can be designed for a given application. For a 2-mm × 2-mm × 1-µm silicon membrane containing sixty bismuth-antimony couples, the structure produces a responsivity of 6 V/W and a time constant of about 15 ms. The use of polysilicon-gold couples can improve the responsivity to nearly 10 V/W while maintaining the same speed, simplifying the process, and retaining compatibility with on-chip signal processing circuitry.

Optimal Design of Transmission Towers Using Genetic Algorithm and Neural Networks

Abstract: In the context of transmission tower optimization, the energy method and the force method are combined in order to form a holistic design and optimization approach, eliminating the need for time-intensive matrix inversion. A migration genetic algorithm is employed in the optimization process. Although this algorithm is suitable for towers with a limited number of elements, it is inefficient in the case of many towers encountered in practice. The addition of a neural network as an analysis tool reduces the overall computational load. Four examples are presented to demonstrate the important role of neural networks in reducing the computational overhead.

Mixed mode fracture toughness testing of PMMA with different three-point bend type specimens

Abstract: Mixed mode fracture behavior of PMMA, was studied experimentally and theoretically using four different test configurations and with different crack types. Although all the test samples were subjected to three-point bend loading but completely different mixed mode fracture behaviors were observed for the tested samples. For each test configuration, especial mixed mode fracture toughness curves were obtained for fracture initiation direction and fracture toughness in the whole ranges of mixed mode I/II loading conditions. The level of crack tip constraint in the tested samples (which is related to the stress intensity factors ( K ) and the T -stress) was used as the main affecting parameter for predicting the mixed mode fracture results based on a two parameter ( K-T ) fracture theory. It was observed that the loss of crack tip constraint in the tested samples increases the mixed mode fracture resistance and decreases the fracture initiation direction and vice versa.

Highly efficient simultaneous ultrasonic-assisted adsorption of methylene blue and rhodamine B onto metal organic framework MIL-68(Al): central composite design optimization

Abstract: In the present work, metal organic framework MIL-68 (MIL = Material of Institute Lavoisier), with metal sites of aluminum ions (namely MIL-68(Al)), was synthesized by a simple, fast and low-cost process for simultaneous removal of Methylene Blue (MB) and Rhodamine B (RhB), regarded to be toxic and even carcinogenic, from aqueous solution. The adsorbent was characterized by FTIR, SEM, XRD, BET and TG analysis. Optimization of significant variables such as pH, adsorbent dosage, initial MB concentration, initial RhB concentration and adsorption time affecting both single and binary dye removal was developed by Central Composite Design (CCD) under response surface methodology (RSM), and the optimized values for these parameters in binary solutions were found to be 6.45, 0.014 g, 60 mg L−1, 15 mg L−1 and 9.9 min, respectively. The kinetics and isotherm of the adsorption were investigated in detail. Maximum sorption capacities of 1666, 1111, 227 and 29 mg g−1 were obtained from the Langmuir isotherms for MB and RhB in single and binary solutions, respectively. The kinetics study results suggested that the sorption of the studied dyes onto MIL-68(Al) follows the pseudo-second order model. According to the reusability test of the adsorbent, dye uploaded MIL-68(Al) can be regenerated using methanol. The regenerated sorbent was used for three cycles use with high performance. The effect of ionic strength on the removal efficiency of the sorbent was also tested with different kinds of salts. The applicability of the sorbent was examined for real samples spiked with specific quantities of both dyes in water from tap water, sea water, spring water and laundry wastewater. The short time required for dye uptake makes this MOF a promising sorbent for simultaneous and rapid removal of dyes even in the real polluted environment.