Sharif Digital Repository

The staggered quantum walk is a type of discrete-time quantum-walk model without a coin which can be generated on a graph using particular partitions of the graph nodes. We design Hamiltonians for potential realization of the staggered dynamics on a two-dimensional lattice composed of superconducting microwave resonators connected with tunable couplings. The naive generalization of the one-dimensional staggered dynamics generates two uncoupled one-dimensional quantum walks; thus more complex partitions need to be employed. However, by analyzing the coherence of the dynamics, we show that the quantumness of the evolution corresponding to two independent one-dimensional quantum walks can be... 

In this work, slag based aluminosilicate geopolymer was reinforced with polymeric fibers including, polyester (PES) (waste tire cap plies), polymeric particles including polyethylene terephthalate (PET) (waste water bottle), styrene-butadiene rubber (SBR) (waste tire), and polyvinyl chloride (PVC) (waste water hose). The tensile and compressive strength of the material was evaluated. Taguchi method was employed to assess the influence of the effective parameters on the mechanical characteristics of the geopolymer composite. QUALITEK-4 software was used to create the L32 orthogonal array with 192 (96+96) geopolymer specimens and 32+32 experiments. Analysis of variance (ANOVA) was utilized to... 

In this study, Glucoamylase production by Aspergillus niger was investigated under solid state fermentation using low cost by-products of agricultural processes as substrate. Highest enzyme production was observed when a combination of wheat bran (WB) and corn flour (CF) was used as compared to WB+ rice bran, WB+ rice flour and WB alone. Several compositions of corn flours were experimented. The best combination of WB in addition of 10% corn flour resulted maximum enzyme activities. Study of the fermentations in flasks revealed 373.3 IU/gds and 41.4 g/l for the enzyme activity and protein concentration respectively under conditions of 30± 1°C, pH 4.7 and time 96 h. Optimum conditions... 

Recently, a new data collection was initiated within the RedDots project in order to evaluate text-dependent and text-prompted speaker recognition technology on data from a wider speaker population and with more realistic noise, channel and phonetic variability. This paper analyses our systems built for RedDots challenge-the effort to collect and compare the initial results on this new evaluation data set obtained at different sites. We use our recently introduced HMM based i-vector approach, where, instead of the traditional GMM, a set of phone specific HMMs is used to collect the sufficient statistics for i-vector extraction. Our systems are trained in a completely phraseindependent way on... 

Alaboratory testing program was conducted to investigate the effects of microstructure on the water retention curve (WRC) and wetting-drying induced volume change in loess. The axis translation and vapor equilibrium techniques were adopted to control suction in the range of 0-400 kPa and 4-140 MPa, respectively. Hysteresis in the WRC of loess was observed for the entire range of suction studied. Compared to re-compacted loess, intact loess exhibits a more pronounced hysteresis in the suction range below 20 kPa, which can be explained by the ink-bottle pore neck effect or constricted pores. The hypothesis is supported by microstructural evidence of mercury intrusion porosimetry and scanning... 

The anionic surfactant linear alkylbenzene sulfonate (LAS) is a major chemical constituent of detergent formulation. Regarding the recalcitrant nature of sulfonoaromatic compounds, discharging these substances into wastewater collection systems is a real environmental issue. A study on LAS biodegradation based on bioelectrochemical treatment and in the form of developing a single-chamber microbial fuel cell with air cathode is reported in the present work. Pretreatment study showed LAS concentration of 60 ppm resulted in the highest anaerobic LAS removal of 57%; so, this concentration was chosen to run the MFC. After the sustained anodic biofilm was formed, LAS degradation rate during 4 days... 

In this research, mathematical modelling of an anaerobic hybrid bioreactor for effluent treatment of a Poly-Ethylene Terephthalate (PET) unit in a petrochemical complex was performed. The developed model included a combination of a biofilm model for describing the substrate kinetics; a fluidized bed model for determination of species profiles along the reactor length and a bioreactor model for particle distribution inside the reactor. The reactions performed in the bioreactor included; i) the polymers hydrolysis; ii) fermentation of the resulting monomers; iii) the volatile fatty acids fermentation to Acetate and Hydrogen and iv) the Methane formation as the final product. The reactor was... 

Ship-in-a-bottle complex of nickel(II) containing the ligand N,N′-bis(2,4-dihydroxyacetophenone)-2,2-dimethylpropandiimine (H 2{salnptn(4-OH)2}) has been synthesized in zeolite Y. The characteristics of the encapsulated complex are identified by the methods of EDX, SEM, XRD, FT-IR and cyclic voltammetry. A catalytic effect in the electrochemical oxidation of glucose, fructose and sucrose, and a blocking effect in stevioside oxidation are demonstrated on the Ni II{salnptn(4-OH)2}-Y/CPE. The effects of some parameters, such as potential scan rate and concentration of carbohydrates are investigated. The rate constants for the catalytic reaction (k′) of carbohydrates are also obtained. The... 

This study deals with the large-scale production of biosurfactant from soybean oil soapstock by Pseudomonas aeruginosa MR01. The production of biosurfactant was carried out in a newly designed bioreactor equipped with recycling flow under three operational conditions. Kinetic studies were conducted at both shake flask and 5-L bioreactor scales during fermentation in a soapstock medium. Mathematical equations were developed to model the kinetic patterns at both scales. RESULT: Statistical analyses demonstrated the goodness of fit, with regression r-squared, R2, between 0.97and 0.99 for different models. Furthermore, biosurfactant concentration in the bioreactor including the recycling flow,... 

Spinning reserve (SR) is one of the most important ancillary services which are needed for satisfying reliability requirements, including the desired level of security in power systems. By definition, spinning reserve is the unloaded section of synchronized generation that is able to respond immediately to serve load. This paper proposes a hybrid DCOPF and harmony search (HS) optimization method as a novel heuristic approach to the joint dispatch of energy and reserve considering the bottling of reserve due to transmission limits. The effectiveness of the proposed method is examined by applying it to the IEEE 30-bus test system. The results obtained using the proposed method are presented... 

Interaction between rock-fluid and fluid-fluid can have a significant effect on oil recovery. Changing the wettability of reservoir rock toward more water-wet or less oil-wet state is one of the expected mechanisms during low salinity water injection (LSWI). pH and salinity are of the most eminent factors of injection water controlling the wettability state of a crude oil/brine/rock system during any waterflooding operation. A small change in pH can affect the surface charges at the rock/water and oil/water interfaces leading to wettability alteration in a porous medium. In this study, the synergic effect of salinity and pH on the wettability state of carbonate rocks is evaluated through... 

Petroleum products which are used in a wide variety of industries as energy sources and raw materials have become a major concern in pollution of terrestrial and marine environments. The purpose of this study was to assess the potential of indigenous microbial isolates for degradation of diesel fuel. Two most proficient bacterial strains among five isolated strains from polluted soil of an industrial refinery were studied. The isolates then were identified as Pseudomonas aeruginosa and Bacillus subtilis using biochemical tests and 16S rRNA gene sequence analyses. P. aeruginosa showed higher biodegradation efficiency than B. subtilis in shaking flask containing diesel-contaminated water. P.... 

The idea of power electronic transformer (PET), which work with solid-state switches, have been considered noticeably recently. Every power electronic transformer has several parts which each of them needs its own reliable supply voltage. So the appropriate performance of a PET depends on the existence of various proper supply voltages. The distributed power supply (DPS), which can produce several different supply voltages simultaneously with various powers and high reliability, may be the optimum choice available for the supply of different modules of a PET. Additionally, distributed energy generation sources may be used as the alternative source for the PET which in that case it's... 

In the present work, the roles of inorganic oxide nanoparticles on the extraction efficiency of polyethylene terephthalate-based nanocomposites were extensively studied. Four fiber coatings based on polyethylene terephthalate nanocomposites containing different types of nanoparticles along with a pristine polyethylene terephthalate polymer were conveniently electrospun on stainless steel wires. The applicability of new fiber coatings were examined by headspace-solid phase microextraction of some environmentally important volatile organic compound such as benzene, toluene, ethylbenzene and xylene (BTEX), as model compounds, from aqueous samples. Subsequently, the extracted analytes were... 

Background: The bio-oxidation of ferrous iron is a potential industrial process in the regeneration of ferric iron and the removal of H2S in combustible gases. Bio-oxidation of ferrous iron may be an alternative method of producing ferric sulfate, which is a reagent used for removal of H2S from biogas, tail gas and in the pulp and paper industry. For practical use of this process, this study evaluated the optimal pH and initial ferric concentration. pH control looks like a key factor as it acts both on growth rate and on solubility ofmaterials in the system. Results: Process variables such as pH and amount of initial ferrous ions on oxidation by A. ferrooxidans and the effects of process... 

A recyclable optical nanosensor was developed by immobilizing L-tyrosine functionalized silver nanoparticles (AgNPs) on the polyethylene terephthalate (PET) substrate for rapid determination of Pb2+ ions. At first, the L-tyrosine functionalized AgNPs were assessed in the solution phase; the response time was lower than 15 s, and a limit of detection lower than 9 nM was obtained in the dynamic range of 1–1000 nM. For fabrication of the optical assay kit, the design of experiment (DOE) was used to optimize the immobilization efficiency of the nanoparticles on PET films by studying AgNO3 concentration and pH as two crucial parameters. The assay kit in optimal conditions showed a sharp localized...