Sharif Digital Repository

Capillary Imbibition is an important mechanism in producing oil from matrix blocks in fractured reservoirs. In a water-wet fractured reservoir, if the rise of water level in fracture is in a way that at all the moments the water front in fracture is lower than that in the matrix block we expect co-current imbibition. Iranian reservoirs have large matrix blocks and co-current imbibition can be expectable. Till this time, not many investigations have been done on co-current imbibition in and out of our country, Iran. In this thesis, an experimental investigation on co-current imbibition will be done for different conditions. The main goal of this thesis is the study of co-current imbibition in... 

One of the main challenges in the design of wireless sensor networks (WSNs) is minimizing the energy consumption while simultaneously maximizing the performance of sensors. In this thesis, we have considered WSNs based on beacon enabled IEEE 802.15.4/Zigbee Standards with low rate applications like temperature, humidity and light sensing, which mainly have been used in a smart home environment, and proposed a cross-layer design to overcome this challenge. The design involves an optimizer module that captures the application layer and MAC sub layer behaviors. Based on these behaviors, the optimizer dynamically changes the rate of node’s traffic at the application layer and the priority of... 

We present a home energy management system that is able to manage home energy demand and resources to achieve minimum household payment in electricity dynamic pricing.Communication is used to collect needed data from the home energy system members and users in order toimprove demand and resources management. Some of the needed data comes from appliances and solar panels by wireless sensor network and some other is received from home users by a user interface.
Two algorithms are proposed that the first algorithm goal is to minimizing household payment and the second algorithm goals are flexible implementiation and decreasing household payment. To decrease household payment, these... 

Today, smart devices have become an integral part of everyday life. The Android operating system is also the most popular operating system of these devices, and as a result, various malwares are produced and distributed for this operating system every day. This makes it especially important to investigate these malwares. This includes finding people involved in the development and distribution of malware, as well as discovering other malwares created by them. Discovering other involved entities, such as social media accounts, websites, Android store accounts, and taking steps to prevent malware from being distributed by them is another aspect of this story. In order to deal with organized... 

Exact and safe structural analysis and design under various loadings is an important issue, which have engaged engineers for a long time. Till now, building design codes have suggested three main methods for seismic analysis of structures, which consist of: Static analysis, Pseudo-dynamic response spectrum analysis and Time history analysis. The first two methods are too approximate, especially in irregular structures which demand exact 3d analyses. The most reliable method is Time history method. With advance of computational tools, engineers tend toward using more reliable analysis methods and using old fashioned rough methods is becoming less popular. One of the issues, which is important... 

Recent studies show that irregular structures have been damaged more than regular ones during earthquakes. This proves importance of seismic response determination of this type of structures. Today, Codes define irregularity in structures and restrict seismic analysis and design of these types of structures. The Endurance Time (ET) method is a time-history based dynamic pushover procedure for seismic analysis and design of structures that has been recently proposed in Sharif University. This thesis illustrates ET capability in analysis and design of vertically irregular frames. Irregular frames with three, seven and twelve story high were designed with two types of mass and stiffness... 

In this research the appilication of a new method named Endurance Time (ET) analysis in seismic analysis of multi span bridges in linear and nonlinear ranges is investigated. Endurance Time is a time history based method of seismic analysis. In this method structure is subjected to an intensifying predefined acceleration function and different damage indices of the structure are evaluated through analysis time. The Endurance Time criterion and the Endurance Time acceleration functions have been generated in previous researchs of ET group. Using 7 earthquake records which are selected from hundred ones of PEER database based on FEMA p695 recommendations, several scaling methods are used to... 

Endurance Time Method (ET) is a type of dynamic pushover procedure in which the structure is analyzed under special series of accelerograms, called ET acceleration Functions (ETAF) and the response of structure is sketched versus time until the collapse state. With evaluating response curve and the time which damage in structure reach the expected value, the final assessment of structure can be made. In this dissertation, the application of ET method for Non-linear 3 dimensional seismic analysis of steel moment frames under earthquake multicomponent excitation is investigated. For this purpose, various patterns of ET loading are investigated and the most appropriate algorithm in... 

Nowadays using traditional hollow clay brick in buildings to make walls and partitionsisvery common. Non-load-bearing walls in buildings are used as architectural elements for design purposes and protecting the people that are inside the building from cold , heat and sound pollution .Due to the new technologies and developing building codes interms of structure , non-load-bearing walls behaviour that is always neglected seems necessary to be considered. In this research we have investigated the static and dynamic behaviour of a patented non-load-bearing wall made up of a claybrick system with specially-designed-precision grooved faces that eliminates conventional cement mortar and results... 

In the earthquake conditions, the collapse of cooling towers can stop power station activities and heavy financial losses that can be led increasing disaster dimentions finally. In this thesis for analysis of concrete hyperbolic cooling towers and generally for analysis of shell structures, the endurance time (ET) method benefits are used. Also with comparision between ET and standard time history method (THA), accuracy and probable errors of ET method are discussed. It should be noted that ET method is a new time history based method of seismic analysis expect that in this method, structure is imposed under specific intensifying acceleration functions. ET method is capabable for nonlinear... 

Endurance Time (ET) is a fairly comprehensive analytical method based on time history analysis applied for evaluating structural systems excited by dynamic loading of earthquake. In such evaluation assessment measure is based on endurance time of structure versus applied accelerogram function and parameters such as stiffness, lateral resistance, period of vibration and dynamic characteristics are not used directly. In this research nonlinear dynamic analysis of elevated steel tanks with laterally braced framed tower under the loading of earthquake records and ET accelerograms was studied and effectivity of ET method in analyzing such elevated tanks was verified. Due to complication of... 

The structure performances during past earthquakes indicate the importance of predicting behaviors of irregular structures under earthquakes. If the irregularity exceeds an expected limit, a seismic analysis should be carried out by a dynamic analysis method. The Endurance Time (ET) is a time-history method, base on dynamic analysis for seismic analyzing and designing the structures, in which structures are subjected to intensifying accelerogram functions and their Endurance Time is measured. One of the most applicable methods for RCF analysis is the Concentrated Hinge Model which is used in this research too. The needed parameters for modeling plasticity in concentrated hinge are achieved... 

In recent years, by development of computer and analytical software, engineers intended to do complicated and delicate dynamic analysis instead of static ones. This cause reduction in uncertainty in structures analysis and designing, that improves environmental, economical, and safety performance. Currently there are two common methods which are accepted in major building codes, they are spectral and time history dynamic analysis which the former analyzes structures by using design code spectra based on determination of structures’ dynamic haracteristics, and the latest do it by imposing ground motions on the structure. The spectral dynamic analysis method has some errors and causes... 

With improvement of design and analysis techniques, use of irregular bridges has been expanded. These improve the aesthetics of urban spaces as well as providing shorter highways in impassables. Horizontally curved bridges are among the type of structures, which needs to be designed based on three-dimensional analysis. In this thesis, three-dimensional nonlinear analysis was performed by Endurance Time Method (ET) on horizontally curved bridges. Nonlinear models have been analyzed under ET acceleration functions. Comparing ET results in DBE level with earthquake responses, the difference between these two methods were determined. ET estimated earthquake responses with good accuracy;... 

The Endurance Time Method is reprehensively new and comprehensive method for analyzing and designing the structure quality in based on performance that is related on time history analysis for investigating structure systems under dynamical instigation in result of earthquake. In this evaluation the index comparison in based on endurance time against of applied acceleration function. The result of the structure will plot against time, until the structure will achieve to a special amount of damage. The high endurance time means high performance. While the damage index will maintain less than allowable limit until endurance time, the structure will be approvable.In this project the ability of... 

Based on special properties of metal dampers such as high energy dissipation, stable hysteric cycles and simple application, low cost, insensitivity to changes of temperature and ability to be substituted after occurring of earthquakes, they are being used for structures control. ADAS and SSD are two kinds of metal dampers which are connected to top of the chevron braces and under the middle of beams. When shear forces are applied, these dampers yield and enter the plastic zone. In Endurance Time (ET) method gradually intensifying acceleration functions are created in a manner that the linear and nonlinear response spectra of them, while being proportional to average of real earthquakes...