Sharif Digital Repository

In this research, Nickel recovery has been investigated from spent catalyst (NiO/Al2O3) in reformers of direct reduction iron plant (Midrex). Genetic Algorithm method was applied for screening and optimization of the parameters affecting on the Ni dissolution in sulphuric acid by means of Design Expert Software. In accordance with the results, temperature, time, acid concentration and particle size were introduced as the effective parameters on the catalyst leaching. In the next step, the optimization experiments, the optimal parameters were achieved as following: Temperature = 95 C, Acid concentration = 5 Molar, Time = 255 minute, Stirring speed = 600 rpm, Particle size = 50-60 micron and... 

The purpose of this study is to analyze the economic, welfare, and environmental effects of the policy of reforming energy subsidies in the industrial sector. The policy of reforming energy subsidies has been examined in the form of 6 scenarios based on the elimination of the current system of payment and redistribution of income among households and producers in certain proportions using a computable general equilibrium model. In the static model, economic variables include variables of production, price and net exports at the industry level and GDP variables, consumer price index, household consumption, government spending, investment, total imports and exports, prices and employment of... 

Spinal cord injury is a systemic disease related to the central nervous system and one of the most severe traumatic diseases that affects a large number of people each year. Inadequate control of the inflammation at the site of injury and the lack of a suitable biomimetic environment are two major and significant factors in the further expansion of the damage. In this research, a polymer/peptide hybrid hydrogel was prepared using a combination of high molecular weight hyaluronic acid and a self-assembling peptide with the IKVAV biological epitope derived from nerve tissue laminin. To create reversible interactions between the polymer and peptide, hyaluronic acid chains were modified with... 

Knowing the time of change would narrow the search to find and identify the variables disturbing a process. Having this information, an appropriate corrective action could be implemented and valuable time could be saved. Multistage processes that are often observed in current manufacturing processes must be monitored to assure quality products. The change-point detection of such processes has not been proposes investigated yet. Thus, this dissertation proposes maximum likelihood step-change estimators of two kinds of these processes. First, a multistage process with variable quality characteristics is considered and formulated by the first-order auto-regressive model. For the location... 

The purpose of this research is analyzing designed experiments which their response variable is in form of multichannel profiles. For this purpose, a number of experiments with multichannel profile response variable designed at first. Then by random effect model, output data calculated. Experiments output data dimension reduced using principal component analysis and its extensions. After that, regression analysis used to analyze results of dimensionality reduction data in order to estimate coefficients of potentially effective variables in response. At the end, coefficients of effective variables classified with a hierarchical classification method in order to discover change and its root...