Slag Prediction in Submerged Rocket Nozzle Through Two-Phase CFD Simulations

A computational procedure has been established to predict the slag in a practical solid rocket motor with submerged nozzle. Both single-phase and two-phase flow analyses have been performed in the rocket motor port. Three-dimensional Navier-Stokes equations along with SST turbulence model have been solved for gas-phase calculations. The effect of ejected alumina particles from the propellant geometry on the flow field has been simulated through Lagrangian tracking method. The computational methodology is firstly validated by comparing against other numerical results of rocket motors available in the literature before applying the same to predict the slag accumulation of a submerged rocket motor for strategic applications. Burn-back geometries at different instants have been simulated and parametric studies were performed to find out the effect of Al2O3 particle size. It was observed that the slag capture rate increases uniformly with A12O3 particle size. The predicted slag accumulation data match closely with the ground test data for the range of conditions simulated in the present work.Defence Science Journal, Vol. 65, No. 2, March 2015, pp.99-106, DOI:http://dx.doi.org/10.14429/dsj.65.714

Image mosaicing of panoramic images

Image mosaicing is combining or stitching several images of a scene or object taken from different angles into a single image with a greater angle of view. This is practised a developing field. Recent years have seen quite a lot of advancement in the field. Many algorithms have been developed over the years. Our work is based on feature based approach of image mosaicing. The steps in image mosaic consist of feature point detection, feature point descriptor extraction and feature point matching. RANSAC algorithm is applied to eliminate variety of mismatches and acquire transformation matrix between the images. The input image is transformed with the right mapping model for image stitching. Therefore, this paper proposes an algorithm for mosaicing two images efficiently using Harris-corner feature detection method, RANSAC feature matching method and then image transformation, warping and by blending methods

Development of high intensity low emission combustor for achieving flameless combustion of liquid fuels

AbstractThis paper presents the experimental and numerical results for a two stage combustor capable of achieving flameless combustion with liquid fuels for different thermal heat inputs of 20, 30, 40 and 60kW and heat release density of 5–15MW/m3. Combustion characteristics and pollutant emissions are studied for three different fuels, kerosene, diesel and gasoline. The influence of droplet diameter on pollutant emissions at all conditions is studied. The fuel and oxidizer are supplied at ambient conditions. The concept of high swirl flows has been adopted to achieve high internal recirculation rates, residence time and increased dilution of the fresh reactants in the primary combustion zone, resulting in flameless combustion mode. Air is injected through four tangential injection ports located near the bottom of the combustor and liquid fuel is injected through a centrally mounted pressure swirl injector. Computational analysis of the flow features shows that decrease in the exit port diameter of the primary chamber increases the recirculation rate of combustion products and helps in achieving the flameless combustion mode. Based on preliminary computational studies, a 30mm primary chamber exit port diameter is chosen for experimental studies. Detailed experimental investigations show that flameless combustion mode was achieved with evenly distributed combustion reaction zone and uniform temperature distribution in the combustor. Pollutant emissions of CO, NOx, CxHy are measured and compared for all operating conditions of different fuels and different thermal inputs. The acoustic emission levels are reduced by 6–8dB as combustion mode shifts from conventional mode to flameless combustion mode

Genome fingerprinting of two populations of Aedes (Stegomyia) albopictus Skuse (Asian Tiger) using random primers (Diptera: Culicidae)

The present paper deals with RAPD-PCR based genomic characterization of two allopatric populations of Aedes (Stegomyia) albopictus Skuse which is a major vector of dengue fever and a source of many other pathogenic infections in man. For the present purpose one population was collected from village Dhunater, Distt. Hamirpur in Himachal Pradesh (pop.A) while the other was procured from Panjab University campus (pop.B). The genomic DNA from the legs of individual specimens was amplified by using three random primers viz: Primer I-5’TTTGCCCGGA-3’, Primer II- 5’-GTCCCGACGA-3’ and Primer III- 5’-CAGGCCCTTC-3’. The amplification of the DNA of pop.A with primer I, produced a total of 7 bands ranging from 230-880 bp while 3 bands ranging from 450-820 bp were produced from pop. B. Similarly, with primer II a total of 8 bands were produced from pop. A, which ranged from 220-800 bp while 9 were produced from the DNA of the individuals of pop. B, which ranged from 200-900 bp. With primer III, a total of 15 bands were produced from pop. A, with a base pair composition varying from 210-1031 bp while 5 were produced from pop. B with a range of 210-370 bp. From the hierarichial cluster sharing analysis of bands, primers I and II were found to ideal for the differentiation of the individuals at the population level studies of this species of considerable epidemiological significance

Antioxidant activity and FT-IR analysis of Datura innoxia and Datura metel leaf and seed methanolic extracts

Background: Datura (family- Solanaceae), has a long history of being used as herbal medicine. These medicinal effects have been attributed to the phytochemicals present in the plant leaves and seeds, in particular alkaloids, flavonoids and phenolic compounds. The objective of this study was to investigate the methanolic leaf and seed extracts of Datura innoxia (DLP-I & DSP-I) and Datura metel (DLP-M & DSP-M) for their total phenolic, flavonoids and in-vitro antioxidant properties.Materials and Methods: Determination of total phenolic content and total flavonoid content and antioxidant activity in terms of total antioxidant assay, ABTS assay, DPPH assay and in-vitro lipid peroxidation inhibiting activity were determined along with the FT-IR (Fourier transform infrared spectroscopy) analysis of the extracts.Results: The highest total phenolic and total flavonoid content were registered by the D. innoxia leaf extract (70.26 ± 1.12 mg GAE/g and 34.24 ± 1.28 mg RE/g respectively). Maximum DPPH radical scavenging activity was exerted by the leaf extract of D. innoxia (IC50 = 146.69 ± 8.46 μg/mL) among the four different methanolic extracts. The highest activity of the ABTS assay was found in Datura innoxia leaf extract (IC50 value = 149.42 ± 13.43 μg/mL) and the highest total antioxidant capacity was found to be present in D. innoxia leaf extract (221.25 ± 1.06 mg AAE/g) whereas D. metel seed extract registered the maximum lipid peroxidation inhibition activity (IC50 = 112 ± 1.30 μg/mL). The FT-IR data also supported the maximum activity in D. innoxia (leaf and seed) extracts.Conclusion: The results thus obtained suggested that the plant Datura innoxia possess considerable antioxidant activity over Datura metel and therefore can be established as a potential source of natural antioxidant.Keywords: Datura species, Methanolic extract, DPPH, ABTS, FT-IR, Antioxidant

Durability of concrete using marble mining waste

The aim of the study was to study behavior of concrete containing marble mining waste under aggressive environment. Waste from marble mining and processing industries was used in concrete as coarse aggregate in combination with conventional coarse aggregate. The particle packing density approach was followed to design the concrete mix and 75% conventional coarse aggregate was replaced by aggregate obtained by crushing waste from marble mining waste. The water-cement ratio was fixed 0.45 for all the mixes. Properties of concrete under aggressive environment such as chloride ion penetration, resistance to sulphates were evaluated. The test results revealed that, resistance to chloride ion penetration and sulphate attack increased as compared to control concrete. Overall the results supported by microstructure analysis indicate that there is no significant adverse effect on the use of marble waste as a coarse aggregate on the durability properties of concrete. The results of fire study reveal that, concrete with marble waste performs better than control concrete up to a temperature of 800 ºC

A PHARMACEUTICO-ANALYTICAL STUDY OF AMRITADYA GUGGULU

Aushadha Kalpana is prepared by different pharmaceutical processing applied to the crude drugs to get the desired therapeutic effects. Guggulu kalpana is one of them. Guggulu is the gummy resin of the Indian plant bdellium i.e. Commiphora mukul. Guggulu is always used after Shodhana to remove its impurities. So the process of Shodhana becomes imperative in different media. In addition to it, Shodhana of Guggulu in different media brings specific properties to Guggulu. Ayurvedic medicines are gaining increase in popularity worldwide for the treatment of various diseases in recent times. In the present study, Amritadya guggulu, one of the Guggulu preparation mentioned in Pidika, Bhagandara and Sthaulya like conditions in Chakkradatta, was prepared and analysed so as to prove the safety and efficacy of the drug. Aims and objectives: To develop standard operative procedure for preparation of genuine drug and to analyze the safety and purity of the drug. Material and Methods: Amritadya guggulu was prepared as per classical texts and analysed by using different parameters like organoleptic properties, physicochemical properties, TLC etc. Discussion and Conclusion: 50% weight loss was observed. The weight loss was due to removal of impurities present in the Guggulu and handling loss. Presence of low acid insoluble ash (1.08%) determines the presence of low adherent dirt as well as sand particles. Presence of low moisture content (loss on drying 6.2%) decreases decomposition and enhances the shelf life and therapeutic value of the drug. Hence it can be concluded that the pharmaceutical and analytical study confirm the authenticity and quality of the drug

Trace elements analysis of Biophytum sensitivum (L.) DC. by EDXRF spectroscopy and its therapeutic role in diabetes mellitus

8-14Minerals and trace elements, as structural components of tissues, play vital role in cellular and basal metabolism. The Little Tree Plant, Biophytum sensitivum (L.) DC., locally called Lajalu, is a well-known medicinal herb, traditionally considered as one of the 10 flowers used since ancient time for healthy life. In Ayurveda, it is used to treat various ailments viz., asthma, insomnia, convulsions, cramps, stomach ache, chest complaints, inflammation, tumours and skin disorders. In this study, we analyzed the elemental contents of its leaves and roots using EDXRF spectroscopy, and tried to find possible correlation with its nutritional and curative effects. The elements Ca, K, Si, Cl, P, and S were found in the highest concentration in leaf, in the descending order, but in the root, K took the leading position. The results have been discussed with reference to the established role of these elements in physiology and pathology of human life with special focus on its role in bone building, controlling the sugar level and wound healing capacity of patients with diabetes mellitus