Sharif Digital Repository

This study seeks to compare the effect of curing conditions in the sea, coast, and middle of the island environment on five mix designs of alkali-activated concrete (AAC) based on ground granulated blast furnace slag (GGBFS) and fly ash (FA) and the effect of the ratio of sodium silicate (SS) to sodium hydroxide (SH) and alkali activated solutions (AAMS) to the binder on mechanical properties. The compressive strength and load-deflection test was conducted to obtain uniaxial compressive strengths (UCS), modulus of elasticity ("E" _"S" ), elastic and ultimate strain, and dissipated energy. The most significant decrease in strength was observed in the coastal area and the sea. Also, the... 

Wireless communication applications need high computing power, flexibility and scalability. Although ASICs have the ability of high computing power but they are not flexible to changing or completing of communication protocols. On the other hand, general purpose microprocessors or DSPs are flexible, but do not provide sufficient computing power. Thus devices with reconfigurable architecture have been proposed as a compromise between ASICs and microperocessors. One of the main features of reconfigurable devices is the granularity. The granularity of a reconfigurable devices shows the amount of computing power incorporate in a processing element. In this thesis we have evaluated different... 

Fracture Toughness of Geopolymer Concrete Containing Blast Furnace Slag in Corrosive Environments  

Material durability is quite critical in corrosive environments. In this study, two hundred and seventy geopolymer concrete specimens with different mix designs were prepared and then wrapped with two different fiber reinforced polymer (FRP) materials. For 12960 hrs (eighteen months), the specimens were exposed to four different pHs (2.5, 7, 7.25, 12.5). The reliability and SEM analysis were performed after modeling the compressive strength over time. Based on the results, the reduction of the compressive strength was up to 22% in an acidic environment. The compressive strength of the specimens was increased up to 11 percent after alkaline solution exposure. The ductility of all specimens... 

Concrete has long been one of the most widely used materials in the world. Cement, as a major component of concrete, due to the use of fossil fuels in its production process, emitting greenhouse gases such as carbon dioxide, which cause air pollution and environmental issues such as climate change. On the other hand, the wastes of industrial factories such as slag of the Blast furnace, due to their large volume and lack of sufficient space for storage of these wastes, lead to the release of these wastes that have alkaline structures into enviroment, causing environmental pollution Such as embankment pollution. Alkali-activated concrete has prevented the release of these pollutant into the... 

Laboratory experiments were carried out to investigate the effect of influent alkalinity and reactor pH on microbial species, morphology and performance efficiency of aerobic granules. The experiments were conducted in two L sequencing batch reactors (R1-R2) with different influent alkalinity and pH medium. pH in R1 ,with high influent alkalinity, was in the range of 7-7.5 and pH in R2 was adjusted in 4.5-5.5. The experimental results demonstrated that the dominated microbial species and structure of granules were different in two rectors. Acidic environment of R2 provide favorable condition for fungal growth and granules formed within first week of operation. On the other hand in R1,... 

The present thesis has provided more fundamental understanding of granulation rate processes (such as coalescence, attrition and breakage) by investigating the effects of operating parameters on product properties. The studied process was wet granulation carried out in two high shear mixer granulators. Granulation duration, binder mass and impeller speed were considered as operating parameters and granule size distribution (measured by sieving) and granule binder distribution (measured by thermogravimetery method) were regarded as product properties. Experiments were conducted in two analogous cylindrical and conical high shear granulators. The obtained experimental and theoretical results... 

Fluidized bed spray granulation is an important powder production process with several key advantages compared to other powder production processes, such as spray drying. Moreover, in fluidized bed granulators, whole process takes place in just one apparatus and there is no need to side processing. Most important characteristics and essential part of fluidized bed granulation is the wetting of primary particles by atomized liquid binder to coating the primary particles and producing granules. To date, a lot of research has focused on modeling and understanding of the separate particle growth mechanisms which have been integrated into the population balance models. Although, these concepts... 

Despite many advantages of granular sludge in anaerobic reactors (e.g. UASB), over the past few years research attention had turned towards developing aerobic granular sludge. Although much research is carried out on the formation of aerobic granules, less work is reported on how to enhance granules characteristics such as increasing in granule size, concentration, durability and stability. The aims of this study are to investigate the effects of cationic polymer on granule formation and the way to improve granule characteristics. For this purpose two SBR reactors (0.15 m diameter and 1.8 m height, R1 and R2) were used by feeding synthetic wastewater (diluted molasses, COD ranging from 1400... 

The aim of the present research is to analyse feasibility study of manufacturing the disposable (Biodegradable) plant containers in Iran. The population of the research consists of the whole capacity for manufacturing this product and the similar product producers which have been registered in the Ministry of Industry, Mines and Commerce. First, in this research, the environmental and anti-environmental impacts of non-plant Disposable Containers like: plastic, foam, paper and aluminum have been discussed and also their disadvantages have been examined to be compared with advantages of using plant Disposable Containers. Thereafter, collecting the required data about today society and market,...