Sharif Digital Repository

Increasing energy consumption and limited energy resources are instances of the concerns of human societies and environmentalists today. The condensation process, as one of the most important processes in the industry, plays an important role in saving and regeneration the existing energy. Nowdays, surface optimization is one of the modern ways to improve condensation.In this research, two methods have been used to construct surfaces useful for enhancement of droplet condensation, including hybrid surfaces and solid infused surfaces. In the construction of hybrid surfaces, superhydrophobic coating with silica nanoparticles based on hydroxyl acrylic resin was used. The superhydrophilic parts... 

The ever-increasing applications of fluids in residential areas as well as in main industries require investment to advance and optimize fluid control and their real-time flow rate monitoring. Numerous methods have been developed for measuring fluid flow rates, particularly for water. This study focuses on the design and evaluation of a sound-based water flow measurement system. As the first test, a microphone was placed on the water pipe, and through time-domain analysis, a second-degree relationship was found between the pressure amplitude of the signal and the flow rate to increase the accuracy of signal processing. Analysis of the signal-to-noise ratio revealed that the vibration of the... 

In this study, three active, passive, and hybrid thermal management systems are applied to a lithium battery module with industrial specifications, i.e., Tesla battery module, and the optimal conditions are extracted. The thermal and electrochemical behavior of battery cells is modeled using the quasi-two-dimensional approach by Newman’s method. The effects of inter-cellular distance on the maximum temperature and on the temperature distribution in the pack as the target variables are thoroughly investigated. A suitable range for the above distances is then determined in order to reduce the overall cooling power and the expected thermal performance of the pack. The results of temperature... 

Low capacity of the batteries is one of the main limitations of using them in different industries and transportation applications. For example, in fully-electrical cars, battery capacity determines the distance that could be proceeded without recharging. Although, it’s possible to increase capacity by increasing battery volume; but in cases that volume or mass is a limitation itself, this is not a practical solution. In fact, what should be considered as the real limitation is the density of capacity of batteries. The improvement in battery capacity means storing more Lithium-Ion in the anode of battery. Silicon has always been noticed as a high capacity material for using in anode. In... 

The primary goal of seismic design requirements of building codes is to protect life safety of occupants during severe earthquakes. Thus it is required that collapse probability of designed buildings to be acceptably low. However current design codes are strength based and intrinsically experimental. Thus collapse safety of buildings designed by these codes is not known quantitatively. The history of formation and update of seismic building codes is marked by big earthquakes; often serving as landmarks for the evolution of seismic codes and detecting its deficiencies. As time passes, the design criteria become more and more articulate and ambitious, just as the design objectives evolve from... 

One of the most efficient methods in stiffening tall buildings to withstand lateral loads such as wind loading is to link the shear resisting core to the exterior columns using outrigger trusses. Many tall buildings such as Taipei 101 have benefited from outriggers. In this system, the outriggers force the perimeter frame to take part in resisting the bending moment of the lateral load acting on the structure by developing axial restraining forces in the windward and the leeward columns of the perimeter frame and forming a resisting moment.Most of the present analytical methods have studied the performance of outrigger braced structures neglecting shear deformation of the shear wall core and... 

Determining nonlinear dynamic behavior of structures is always one of the main goals of structure and earthquake engineers. The Modal Incremental Dynamic Analysis (MIDA) is one of the newest methods for analyzing the seismic behavior of structures. Indeed, this method has superseded the exact IDA method which is too complicated and prolix. Although, this method represents approximate results, high accuracy, fastness and low cost procedure made it an efficient and useful technique. Many researchers have used this method and investigated the accuracy of that and achieved proper results. Up to now no one has applied this method on structures which are equipped with dampers. In the procedure of... 

Existing design methods for steel frames has been improved over the last three decades in order to incorporate the behavior of semi-rigid steel connections in furtherance of frame design and since the analysis and design of structures is often done based on the assumption of completely rigid or pinned behavior,therefore, the actual behavior of connections and their modeling can help to understand the actual behavior of structures.Knowledge of the initial rotational stiffness of the connection is important for elastic analysis of structures. Investigations show that structures with semi-rigid connections have many features which are the causes to prefer these kinds of connections to the... 

To investigate the accurate performance of a structure, the knowledge of the way its connections function, is of great importance. Moreover, cognition of the actual behavior of connections which is often semi-rigid can lead to better apprehension of the actual and more accurate behavior of structures, whilst it is often considered to be pinned or fully-rigid.Therefore, in this study a new semi-rigid steel connection of beam to column will be introduced, and its behavior will be investigated using commercial finite element packages along with mathematical approximate modeling methods. One of the features of this connection is that its behavior mainly depends uponfolding of top and bottom... 

Iron is a common impurity in copper minerals. The presence of iron in hydrometallurgical copper PLS causes continuous reactions between Fe(II) and Fe(III) ions. In order to improve energy efficiency and product quality iron removal shall be done. In this study separation of iron from Sarcheshme copper leaching liquor containing 6 g/L Fe, was conducted by solvent extraction using D2EHPA in kerosene. Chloric acid solution was used to strip the loaded iron from organic phase. Results of extraction experiments designed by taguchi method showed 92.49% iron recovery and 2.44% copper extraction under optimum condition. Using same method for stripping experiments, it was found that variation of time... 

Steel plate shear walls (SPSWs) are popular lateral force resisting systems whose practical applications range from high seismic regions to medium and low seismic areas and wind load applications. The factors which make SPSW attractive include its energy dissipation capacity, excellent ductility, constructability, speed of construction compared to concrete shear walls, reduced architectural footprint compared to concrete shear walls, and increased inelastic deformation capacity as compared to braced frames and concrete shear walls.
In this research, characteristics and behavior of un-stiffened perforated SPSWs using non-linear finite elements software has been investigated. In order to... 

Despite all the developments of construction industry, there are some limitations in this important industry. For example, one of the common limitations of buildings is restrictions of architectural designs that often rise due to location of lateral load-resisting systems of buildings and usually rise disagreement between structure and architecture engineers. The lateral load-resisting systems and location of them are very important, therefore, in this study we attempt to investigate the changes of their location in structure’s stories. Due to architectural restrictions, the removal and movement of lateral load-resisting systems have been done only in some stories or from a story to the... 

Steel bracing systems can be used effectively for seismic retrofitting of existing RC buildings as well as for seismic design of new building. Steel bracing system has been used to increase the lateral load resistance of steel structures. In recent years the concept of steel bracing has also been applied to the retrofitting of reinforced concrete frames, especially to improve seismic performance of non-ductile reinforced concrete buildings. The use of steel bracing systems for seismic rehabilitation of RC frames offers some advantages such as (a) minimal added weight to the structure; (b) ease and speed of construction;(c) increased architectural flexibility; in comparison with RC shear... 

In this thesis, the semi-hinged connections such as double-angle connections, which are welded to the beam web and bolted to the column flange, are investigated. In this study it's tried to establish the effect of clearance setback between beam end and column flange and/or web. When the beam rotates, it is desirable to avoid the bottom flange of the beam bearing against the column as this can induce large forces in the connection. The usual way of achieving this is to ensure that the connection extends at least a few millimeters beyond the end of the beam. For this purpose, several connections are designed and considered, based on two different shear capacities for the beam. For each... 

Structures having buckling restrained braces (BRB) as earthquake resisting system, have the qualities of high lateral stiffness and the ability to damp the energy coming from earthquake, at the same time.In addition to new structures, these braces can also be used in rehabilitating old steel or concrete buildings. By using this kind of resisting system, smaller sections are needed in design of buildings and also the cost of repair after earthquake can be highly reduced.The most important advantage of buckling restrained braces is their equal behavior and capacity in both tention and compression, that causes high energy absorption as a result of symmetric and stable cyclic behavior. All these... 

Successful treatment of bone infections is a major orthopedic challenge due to the physiological and anatomical features of bone. In this project, we prepared a drug delivery system with injectable and biodegradable polysaccharide agar containing alginate, polyvinyl alcohol and hydroxyapatite nanocarriers composite microspheres. Alginate and polyvinyl alcohol composite microspheres are crosslinked by calcium and freeze-thawing technique. Using the freeze thawing process for polyvinyl alcohol crosslinking, in addition to alginate crosslinking, improved hydrogel swelling behavior and enhanced drug loading and thus slowed drug release, drug loading increased with increasing PVA percentage from ... 

OBS1 frame is a concentric bracing system that consists of three elements, and it provides openings for building using a y-form structure. In the present thesis, the OBS system has been accompanied by a smart damping system.The buildings in which this lateral bearing system is employed are considered as SCBF frames. According to design guidelines, seismic performance parameters are required to design these buildings, including response modification coefficient (R), over-strength factor (Ω) and displacement amplification factor (Cd). This thesis aims to quantify these parameters and evaluate their accuracy based on the method proposed by FEMA-P695. In this method, first, the required initial... 

One of the advantages of Steel Plate Shear Walls (SPSWs) is the possibility of using openings with varying sizes in the infill plates depending on a need basis. Openings are used for various reasons, such as the possibility of installing utilities and for architectural reasons. However, the latest research studies suggest that the use of large-sized openings in infill plates calls for the use of heavy stiffeners or special measures for ensuring system stability. The seismic behavior of two SPSWs with large unstiffened opening (one with a rectangular opening in the middle of the plate and the other with two oval openings on the sides of the infill plate) was studied experimentally and...