Dual mode control of inverter to integrate solar-wind hybrid fed DC-grid with distributed AC grid

Abstract: This paper presents integration of solar-wind hybrid fed DC-grid to distributed AC grid. Generally, the renewable hybrid energy systems use two or more energy sources to supply power to the dc grid. In case of insufficient power generation or excessive load demand, in order to supply power to DC loads, it must integrate with AC grid. As dc loads increase in number, complexity increases and tighter voltage regulation is required. This paper presents dual mode control operation of inverter which integrates the solar and wind power fed dc bus to the single phase ac distribution system. The inverter can be operated in hysteresis current control when power is fed from DC grid to AC distributed grid and in AC-DC boost rectifier mode otherwise. The detailed operation of dual mode control of inverter is described in this paper. The effectiveness of the proposed system has been verified through simulation studies using MATLAB/SIMULINK

On leap Zagreb indices of some cycle related graphs

Let G = (V, E) represent a graph. The 2-degree of a vertex v in G is the number of vertices which are at distance two from v and denoted by d₂(v). The leap Zagreb indices are the recently introduced distance-based topological indices defined using 2-degrees of vertices in G. In this paper, we compute the leap Zagreb indices of some cycle related graphs, namely book graph, cycle with parallel chords, cycle with parallel Pk chords, shell graph and shell type graphs.Publisher's Versio

Single-phase seven-level stack multicell converter using level shifting SPWM technique

Abstract: This paper presents a single-phase seven-level stack multicell converter (SMC) which provides a viable solution for multilevel converter. Conventional cascaded multilevel inverter (MLI) removes the drawbacks of clamping diodes and clamping capacitors topologies. However, in a cascaded MLI number of voltage source and power switches increases as the number of level increases. The main advantage of single-phase SMC converter is only two DC sources are needed for any number of levels. Level shifting SPWM technique has been incorporated to achieve gate pulses, in which carrier wave of 20kHz is compared with 50Hz sinusoidal reference wave at a modulation index of 1 and 0.9. Total harmonic distortion (THD) for SMC converter is achieved at 1.55% and 5.26% with and without filter respectively. The seven-level SMC topology is simulated in MATLAB/SIMULINK and simulation results are provided to verify the performance

Standardization and quality evaluation of Vitamin C enriched poppy seed syrup

146-152The vitamin C enriched poppy seed syrup was developed by incorporating poppy seed slurry at 5-25% with addition of lemon juice. The sensory evaluation of developed products shows that the syrup was found to be acceptable upto 10% incorporation of poppy seed slurry. The syrup found to contains significantly enormous amount of dietary fibres, vitamin C and vitamin E, when compared to commercial samples. The standardized product was subjected to shelf stability evaluation at 23 ± 4 and 37 °C. The physico-chemical evaluation of stored syrup shows that the TSS, total, reducing sugars and colour intensity significantly increased during the entire storage period; while protein, vitamin contents, viz. C and E significantly decreased at above temperature conditions. Slight reduction in acidity and dietary fibre content was notice during storage. Vitamin C enriched poppy seed syrup was found to be acceptable up to 6 months at room temperature and 2 months at 37˚C. The microbial population of stored samples was found to be non detectable

Development of spiced seabuckthorn [<i style="mso-bidi-font-style:normal">Elaeagnus rhamnoides</i> (L.) A. Nelson syn. <i style="mso-bidi-font-style:normal">Hippophae rhamnoides</i> L.] mixed fruit squash

132-141Spiced seabuckthorn mixed fruit squash was developed by blending seabuckthorn juice with pineapple and grapes in varying proportions maintaining a constant total soluble solids, juice and acidity contents in the final product. Among all the blends, the seabuckthorn-pineapple combination exhibited the highest sensory scores. The shelf stability of the spiced squash samples was evaluated under ambient as well as at 37°C temperature conditions upto a period of 6 months. The physico-chemical properties of the spiced seabuckthorn-pineapple mixed fruit squash such as total soluble solids, reducing sugars and browning significantly increased during storage, while vitamin C, vitamin E, total phenols, total carotenoids, total anthocyanins and acidity contents significantly decreased. Accelerated temperature storage condition, i.e. 37°C pronounced more effect in terms of physico-chemical changes when compared to ambient temperature condition of the stored products. The spiced seabuckthorn-pineapple mixed fruit squash was acceptable upto 6 months under ambient temperature conditions when packed in PET bottles. The TPC count, yeast and mould count significantly reduced during entire period of storage, while spores and coliform count was found to be non detectable at both the storage conditions. The microbial load of stored spiced squash under these conditions was found to be within the acceptable limits

Processing seabuckthorn fruit for antioxidant rich jam development and shelf stability assessment

335-346Seabuckthorn [Hippophae rhamnoides L. <span style="font-size:8.0pt;color:black;mso-ansi-language:EN;mso-bidi-font-weight: bold" lang="EN">syn. Elaeagnus rhamnoides (L.) A. Nelson] fruit was processed for development of antioxidant rich jam by employing response surface methodology as a statistical tool. The ingredients, viz. sugar and carrageenan were chosen as independent variables, while sensory attributes, i.e. taste and consistency as dependent variables. Effects of various independent variables on chosen response show that the ingredient sugar had more prominent effect on taste score and carrageenan on consistency score, respectively. The optimum conditions to yield maximum scores of taste and consistency of jam were sugar of 85 gm and carrageenan of 3.4 gm per 100 gm of recipe. Jam contains more natural antioxidants with good texture when compared to commercial products. Shelf stability of jam shows that significant changes in nutritional constituents were observed except acidity and pH during the entire storage period. The microbial population of stored sample was found to be non detectable and product showed a stability of 8-months at room temperature. </span

Optimization of Ingredients for Development of Squash from Seabuckthorn Fruit

785-789Seabuckthorn fruit was optimized for development of squash by employing response surface methodology as a statistical tool. The ingredients viz., sugar and citric acid were chosen as independent variables, while sensory attribute i.e. taste as dependent variable. Effect of various independent variables on chosen response shows that the ingredient citric acid had more prominent effect on taste score than sugar syrup. The optimum condition to yield maximum score of taste of squash was sugar syrup total soluble solids of 60° brix and citric acid of 0.5 g per 100 g of recipe. Squash contains more natural antioxidants and exhibited more antioxidant activity when compared to commercial products

Dose dependant differential anti insect activity of lactone glycoside, a potent plant derived molecule

ABSTRACT Lactone glycoside, the active ingredient present in Cleistanthus collinus (Roxb.) Benth. possessing variety of anti insect properties like antifeedant, insecticidal and insect growth regulatory activity was bioasayed on third, fourth and fifth instar Spodoptera litura Fab. larvae to determine its median effective concentrations. Median deterrency index (DI 50 ), median lethal concentration (LC 50 ) and median emergence inhibition (EI 50 ) were worked out for antifeedant, insecticidal and insect growth regulatory activity respectively through regression and probit analysis. The anti insect activity was dose dependant. The activity varied with increase in concentration in the following order viz., insect growth regulatory, insecticidal and antifeedant action while Median emergence inhibition was at 0.17 ppm, 0.26 ppm and 0.38 ppm, median lethal concentration and median deterrency index were at 1.02 ppm, 1.71 ppm, 2.045 ppm and 60.66 ppm, 68.47 ppm, 71.10 ppm for third, fourth and fifth instars respectively. Further, the activity was also found to be age dependant. As the larval age increased, the required median effective dose also increased. Multi pronged anti insect activity of the lactone glycoside was compared with other botanicals and discussed in detail