Archives-April 2013

In the present investigation the methanol extract of the flowers of the medicinal plant Couroupita guianensis was evaluated for its antimicrobial efficacy and phytochemical contents. The results of the antimicrobial activity showed effective inhibitory activity against Staphylococcus aureus, Plesiomonas shigelloides, Vibrio mimicus, and Proteus vulgaris. Moderate antimicrobial activity was recorded against E.coli, Salmonella typhi and Klebsiella pneumoniae. Preliminary phytochemical analysis of the flower extract of this plant showed the presence of phytoconstituents such as carbohydrates, protein, alkaloids, terpenoids, phenolic compounds, reducing sugar and triterpenoids. The alkaloids present in the crude flower extracts of this plant Couroupita guianensis is profoundly expected for its potential antimicrobial activity.

Polyaniline (PAni), shows a unique feature, that it can be modified in a controlled manner by adding electrolyte. The effect of electrolytes like LiCl, NaCl and KCl on the doping behaviour of Polyaniline emeraldine base (EB) has been investigated. The study of the effect of ultrasonic waves on electrolyte - Polyaniline picrate (PAPI) mixture and their interactions were compared.

Polyaniline salts were synthesized via chemical polymerization and are subjected to ultrasonic waves of 3 MHz. The physicochemical parameters like density, viscosity and compressibility parameters were measured and their effect on ultrasound has been extensively studied. Solvent properties and the spectroscopic properties such as ?max, frequency shifts have been correlated. A study of effect of ultrasonic waves on the organic acid doped PAni has also been attempted.

The use of fibrous material is effective in increasing the surface area of the support media in fixed film reactors. Several fibrous biomass support mediums are available for use in attached growth system .one of these support materials are areca fibers. In this study the experiment was conducted for a batch mode of operation. The bio-reactors were continuously aerated and fed with residential wastewater having an initial average COD of 860 mg/L, BOD of 450 mg/L and NH3-N of 70 mg/L. This present study reveals the study of COD, BOD and NH3-N removal in two reactors, one filled with gravel bed and other areca fibers. Two sets of experiments were conducted to study the effects of detention time, elevated NH3-N concentration. The reactors with gravel bed and areca fibers showed reasonable amount of COD removal (72-74%), BOD removal (92%-94%) and NH3-N removal (58%-60%) within 4-16 hrs of detention period. In both the reactors denitrification was almost absent. Here comparative study of both reactors has been done and it is hypothecated that at fixed MLSS concentration of 2210 mg/L, efficiency of areca fibers bio-reactor seems to be satisfactory and effective for batch mode of operation.

The present study was conducted to study the effect of Structure Reviewing strategy as a direct vocabulary learning strategy on reading comprehension skill. To fulfill the purpose of the study, a language proficiency test was administrated to100 male and female university students who studied in a course other than English as their major in Omidiyeh Islamic Azad University. Ultimately, thirty pre-intermediate students were selected and assigned into two experimental and control groups. The experimental group was taught vocabulary through Structure Reviewing as a direct vocabulary learning strategy for developing their vocabulary storage in reading comprehension. After ten sessions of treatment, the two groups were given a post-test of an achievement vocabulary test. Data analysis was conducted through samples t-test statistics. It demonstrated that the experimental group who utilized Structure Reviewing as a direct vocabulary learning strategy outperformed the control group.

Reduction in the number of component is a live problem in the domain of power electronics, as it is directly leads to reliability implication. Further reduction in active switches in the inverter topology is also beneficial for the cost factor point of view. In view of this, the present paper reports a novel inverter topology based on only four active switches as against the six switches topology widely reported in the literature. The said design is verified using PSIM software. The result shows good resemblance between our proposed four switches topology and conventional six switches topology.

Biogas, a clean and renewable form of energy could very well substitute (especially in the rural sector) for conventional sources of energy (fossil fuels, oil, etc.) which are causing ecological–environmental problems and at the same time depleting at a faster rate. Despite its numerous advantages, the potential of biogas technology could not be fully harnessed or tapped as certain constraints are also associated with it. Most common among these are: the large hydraulic retention time of 30–50 days, low gas production in winter, etc. Therefore, efforts are needed to remove its various limitations so as to popularize this technology in the rural areas. Researchers have tried different techniques to enhance gas production. This paper reviews the various techniques, which could be used to enhance the gas production rate from solid substrates.

In this paper, a testable design with good fault identification capability is used for analysis and diagnosis of stuck-at and bridging faults in Exclusive-OR Sum of Product Reed-Muller canonical circuits, independent of the function for a given number of inputs. Factors of identifiability and distinguishability have been defined and determined. Further, a compact method of representing the circuit outputs has been adopted for ease of tabulation and comparison. Simulations of Single stuck-at, Double stuck-at, OR-bridging and AND-bridging faults for a few random functions have been carried out through MATLAB coding. From the test results, it was found that the fault detection for the set of random functions was more than 95% for most of the functions except few cases, with just n+5 test vectors compared to 2n test vectors required for conventional testing. The location of the fault can also be diagnosed through the output sets.

This study by using of fuzzy approach has attempted to model for predicting the risk of tourism in a fuzzy environment developed for this purpose , at first , the effective parameters of the process of determining the number of tourism in metropolises are recognized , then the variables are classified in 11 categories and according to experts’ opinions , their importance is identified by DEMATEL technique that it is reduced to 14 variables and classified to 4 groups, and considered as an input. Following the classification each with by using membership functions of linguistic variables were transformed into qualitative variables. Each variable in the fuzzy sign in fuzzy networks finally, each of the output variables of the fuzzy system derived. After the Create 11-fuzzy network, each output results as an affecting factor on main risk associated with specific weight and then the weight relation each of the small risks, the main risks was obtain. The end Tehran city as a case study assessment Tehran, with a 50.503% (average) tourism risk whit human-induced has been calculated. It should be noted that these rhythms were in various cities and countries, is different.

Cloud Computing (CC) is emerging as the next generation platform which would facilitate the user on pay as you use mode as per requirement. It provides a number of benefits which could not otherwise be realized. The primary aim of CC is to provide efficient access to remote and geographically distributed resources. A scheduling algorithm is needed to manage the access to the different resources. There are different types of resource scheduling technologies in CC environment. These are implemented at different levels based on different parameters like cost, performance, resource utilization, time, priority, physical distances, throughput, bandwidth, resource availability etc. In this research paper various types of resource allocation scheduling algorithms that provide efficient cloud services have been surveyed and analyzed. Based on the study of different algorithms, a classification of the scheduling algorithms on the basis of selected features has been presented.