Sharif Digital Repository

In this research, we have studied optimization of culture medium and process factors for high alkaline protease production from Bacillus subtilis ATCC 6633 for detergent usage. Five parameter soy bean meal, initial pH, agitation rate, MgSO4, CaCl2 were selected for more studies. At first, one-factor-at-a-time method was applied to investigate effect of each factor separately. Then, optimum condition for maximum protease production was achieved using Minitab software Box-benhnken procedure. According to results, high protease production was seen in soy bean meal, 35 (g/L); MgSO4, 1 (g/L); CaCl2 , 1.5 (g/L); initial pH, 7; agitation rate, 150; inoculum ratio, 12% (v/v). The activity of the... 

For supersonic inlets with reduction of mass flow ratio to a specified value self-induced oscillations know as Buzz would occure. Study and suppression of these oscillations are categorized in the field of inlet stability. In this work performance and stability of a supersonic inlet is studied experimentaly. Also a flow control mean is examined for stability and performance improvement. Investigation of the effect of bleed location as a key parameter for this flow control method is the main goal of this study. The model used is an axisymmetric mixed compression inlet. Experiments were done in 3 freestream Mach Numbers of 1.8, 2.0 and 2.2 with application of bleed and in no-bleed condition.... 

In this project the RGO/Ag2O/g-C3N4 nanocomposite was synthesized, and characterized by different technique such as SEM, XRD, and FT-IR. Then its photocatalytic activity was investigated. The degradation percent for Acid-Blue 92 by this photocatalyst was estimated 81 in 45 minutes. Afterward, the photocatalyst activity was determined in different pH including 4, 7, 10. The best result was for pH=7. Then, the increasing concentration of dye were investigated and the results show that by increasing the concentration of 10 to 30 ppm, the photocatlytic activity decreased. Photocatalytic degradation process of AB92 were also carried out at different amount of photocatalyst. The mechanism of... 

LFP characteristics have been shown to be informative of sensory stimuli and influenced by attention. We show the gamma power in area MT is selective to motion direction showing a Gaussian tuning curve. Here we show for the first time, some evidence based on a single monkey’s data that spatial attention enhances the tuning curve based on gamma power.The synchronization of activity across neurons has been a focus in many recent studies of information processing in networks of cortical cells and areas. One aspect of such inter-neuronal synchrony is the locking of spiking activity to local field potentials (LFPs). Such an interaction has been observed between the timing of individual action... 

A novel Fe3O4/poly (aniline-naphthylamine) (ANI-NA)-based nanocomposite was synthesized by chemical oxidative polymerization process as a magnetic sorbent for magnetic solid phase extraction. The extraction efficiency of this sorbent was examined by isolation of rhodamine B (RhB), a mutagenic and carcinogenic dye from aquatic media in dispersion mode. The efficiency of the synthesized Fe3O4/copolymer composite was examined and compared with Fe3O4/polyaniline (PANI) and Fe3O4/polynaphthylamine (PNA) by quantification of RhB using spectrofluorimetry. Among them, Fe3O4/poly (ANI-NA) nanocomposite showed a prominent efficiency. The scaning electron microscopy (SEM) image of the synthesized... 

Inherently safer design is the new approach to maximize the overall safety of a process plant. This approach suggests some risk reduction strategies to be implemented in the early stages of design. There are different well-established strategies for making a process plant inherently safer. The benefits of applying these strategies on reducing the overall risk inside a plant are obvious. However, some of these changes are rejected many times because they appear to be too costly. But if the effects of applying inherently safer design strategies are investigated not only on the processing costs of a plant but also on the potential accident costs, the decision would in fact be different. In this... 

In the current status of the world production business, any action that can improve quality or decrease the price of products is very important to manufactures. Therefore, many studies had been conducted to do this. In production stages, the assembly stage includes 30% of production cost and up to 40% of production time. Therefore, optimization and design of the Production sequence of this stage are very important. This matter is more important in complicated and multi-segmental productions such as car manufacturing, the Aviation industry, and the shipbuilding industry. Also, optimization of the Production sequence could improve product quality. In this study, an algorithm has been purposed... 

In this research, we study one of the challenges in the field of software engineering, namely the detection of diplicate questions in Stackoverflow, the Q&A community of programmers. The works done in this area has problems such as complexity and reduced performance over time. The proposed solution is based on machine learning and modern representation learning methods. Representation is done with two approaches, domain specific learning and transfer learning. Fasttext and GloVe, the two word embeddings used in domain specific learning, and in transfer learning, the embedding of the universal sentence encoder has been used. Support vector machine and multilayer perceptron used as...