Sharif Digital Repository

Lateral forces on structures are transferred to braces as tensile and compressive loads. These loads enter the beams and columns through the gusset plates. The gusset connections to the beams and columns must be such that they be able to pass the loads through themselves. So far, five analytical models have been proposed for this connection and only one of them is recommended by AISC. These models estimate the existing forces and moments on the connection. The analytical models are: model 1 (KISS), model 2 (2A-AISC), model 3 (Thornton), model 4 (Ricker) and model 5 (Richard). Among these models, only model 3 is recommended by AISC because the others are more conservative. It should be noted... 

Porous thin films have becom very atractive due to their applications in many types of electronic and optical devices. There are several methods for deposition of such films. Chemical method for deposition of nanoporous thin films are relatively simple, but usually hard to control. In this thesis, chemical deposition of thin porous Molybden films is reported. In addition, an available sputtering system has been modified and, controlled porosity thin films were then deposited on glass and silicon substrates using GLAD method.These films have been characerized, and compared with chemically deposited porous thin films  

A kind of novel nanofiltration membrane process is proposed to solvent recovery from dewaxed lube oil stream in an energy-saving way. Most of the nanofiltration membrane materials are polymeric and cannot survive harsh conditions, for example, MEK contained solvents. Hence, high solubility of most of the polymeric materials in the solvent, especially in the MEK, is a challenge to researchers. To prepare a polymeric membrane that can solve the problem integrally skinned polyaniline (PAni) membrane was cast on a woven polyester backing material, and then crosslinked in two different ways, chemically and thermally, to make the membrane resistant in MEK (methyl ethyl ketene) and toluene for long... 

The prediction of deposition efficiency of submicron particles in the pulmonary alveoli has received special attention due to its importance for drug delivery systems, and for assessing air pollutants health risks. In this work, the pulmonary alveoli of a healthy human are idealized by a three dimensional honeycomb like configuration and a fluid-structure interaction analysis is performed to study the normal cyclic breathing hydrodynamics. A viscoelastic model is used for the mechanical behavior of alveolar wall tissue. In contrast to previous works in which the inlet flow rate is predefined, in this model a negative pressure is imposed on the outside surface of the alveolus which causes air... 

This study investigates the dynamic adsorption of asphaltene-in-toluene solutions on pack of wet calcite. All experiments were performed on mineral packs in sand-pack with mesh sizes between 100 to 140 (105 to 150 micron) and porosities between 40 to 46 percent. A UV–vis spectrophotometer was used to monitor the outlet concentration of asphaltenes. Experiments were performed for seven ionic strength of sodium chloride (6 to 1500 mM), five ionic strength of sodium sulfate (6 to 2400 mM) and four ionic strength of these salts mixture (12 to 3300 mM). In previous experiments the asphaltene concentration is 500 mg/l. Also two experments were performed with asphaltene concentration of 2000...