Photon redshift and the appearance of a naked singularity

In this paper we analyze the redshift as observed by an external observer receiving photons which terminate in the past at the naked singularity formed in a Tolman-Bondi dust collapse. Within the context of models considered here it is shown that photons emitted from a weak curvature naked singularity are always finitely redshifted to an external observer. Certain cases of strong curvature naked singularities, including the self-similar one, where the photons are infinitely redshifted are also pointed out.Comment: Latex file, 14 pages, no figures, one change in the reference. Accepted for publication in Phys. Rev.

Assessment of roof water harvesting potential of Navsari city of Gujarat State, India by Remote sensing and Geographic information system (GIS)

Due to the water scarcity scenario in many parts of the Navsari city, Gujarat State in India, it is imperative to adopt cost-effective technologies that could harvest rainwater for satisfying drinking water requirements. The study was conducted with the aim of assessing the rainwater harvesting potential of Navsari city using remote sensing and Geographic Information System (GIS). The built-up areas of Navsari that could harness rainwater were identified by remote sensing and GIS. The effective built-up area contributing to rainwater harvesting was found to be 3.37 km2. The classification was carried out using “Remap” to assess the extent of the built-up area. The city was divided into equal grids and classification of each grid was implemented. The ground truth data was used for the evaluation of the built-up area. The roof water harvesting potential was estimated considering the average annual rainfall of 1621 mm and adopting suitable runoff coefficients. The rainwater harvesting potential of roofs for rainfall of different probabilities was estimated. For return periods of 10 years, 25 years, 50 years and 100 years, the roof water harvesting potentials were estimated to be 0.226, 0.261, 0.287 and 0.312 Million Cubic Metres (MCM), respectively. The estimated average roof water harvesting potential of Navsari city was 164 million litres per year, capable of satisfying the drinking water demand of approximately 1.12 lakh people annually. The rainwater harnessed from the rooftop could augment the current water supply and immensely help in fulfilling the drinking water demand of Navsari

Calcined Phosphate Fertilizer from Jhamarkotra Secondary Phosphate Ore and Rock Phosphate Beneficiation Plant Bulk Circuit Tail

The secondary phosphate ore of RSMML 's Jhamarkotra rock phosphate mines have high iron content that renders it unsuitable for manufacturing of phosphatic fertilizers like SSP,DAP and phosphoric acid. This paper explores the feasibility of utilizing the secondary phosphate ore by thermal treatment, which involves calcination as well as fusion. The calcined and fused products both have good citrate solubility and thus have a potential to be used as a citrate soluble phosphatic fertilizer. This paper also deals some phosphate resources which are added during thermal treatment. These additives not only assist in the fusion and calcination but also improves soil fertility. These are more beneficial to the soil. Calcined dolomite tailing among these has a potential to be utilized as citrate soluble phosphate rich magnesium fertilize

Anthelmintic Activity of a Polyherbal Preparation

The present study was done with the aim to investigate the anthelmintic activity of polyherbal formulation containing herbs Thespesia populnea (bark), Terminalia alata (bark), Clematis triloba (roots) and Ceratophyllum demersum (leaves) using adult earthworm Pheritima posthuma. The aqueous and ethanolic extract of the crude drug of different concentration were tested which involve determination of paralysis time and time to kill the worms. Piperazine citrate was used as standard and it was found that the PHF ethanolic extract activity is higher than PHF aqueous extract

Effect of Twin Vertical Stabilizers on Lateral Directional Static Stability of an Aircraft – A Computational Study

The advantages of twin vertical Stabilizers over a single vertical Stabilizer of an aero plane are the rationale for this study. For conventional aero planes, the use of double vertical Stabilizers is being considered. The contribution to lateral stability has been examined for this application. XFLR5 software was used to conduct the overall analysis. The analysis was conducted for a single vertical Stabilizer as well as twin vertical Stabilizers, and the findings were compiled and correlated. It is critical to be able to fully explain and evaluate the stability and control parameters. It is crucial to understand the relationship between the aerodynamics of the airframe and its stability characteristics in order to increase flight endurance and deployment effectiveness. The stability analysis based on the dynamic model of the twin boom vertical Stabilizer is presented in this paper. The lateral-directional stability of an aero plane with a single vertical tail is determined to be 20% more efficient than that with twin boom vertical Stabilizers. The trim condition is moderately satisfied by an aircraft with twin vertical Stabilizers

Simplified Production of Large Prototypes using Visible Slicing

Rapid Prototyping (RP) is a totally automatic generative manufacturing technique based on a “divide-and-conquer” strategy called ‘slicing’. Simple slicing used on 2.5-axis kinematics of the existing RP machines is responsible for the staircase error. Although thinner slices will have less error, the slice thickness has practical limits. Visible Slicing overcomes these limitations. A few visible slices exactly represent the object. Each visible slice can be realized using a 3- axis kinematics machine from two opposite directions. Visible slicing is implemented on Segmented Object Manufacturing (SOM) machine under development. SOM can produce soft large prototypes faster and cheaper with accuracy comparable to that of CNC machining.Mechanical Engineerin

Transient simulation of LBE cooled CHTR under natural circulation with 3D multi-physics code ARCH-TH

India is developing a 100kWth Compact High Temperature Reactor (CHTR) to facilitate demonstration of technologies for high temperature process heat applications. CHTR is being designed as thorium based TRISO fueled and beryllium oxide moderated prismatic block type vertical core cooled with lead-bismuth eutectic (LBE) under natural circulation for 1000°C outlet. The new concept of high temperature core requires multi-physics multi-scale modeling based tools for investigating the normal operational behavior as well as anticipated transients of CHTR. In view of that, 3D multi-physics code ARCH-TH is being indigenously developed and validated for coupled neutronics-thermal hydraulic benchmarks. The multi-group diffusion based neutron kinetics in code ARCH-TH is integrated with thermal-hydraulic (TH) capability considering 1D- radial heat conduction in multi-channel system. The 1D based hydraulic in the code is capable to simulate the natural circulation phenomena of coolant in coupled parallel multi-channel system. The steady state operation and case of unprotected transient of control rod withdrawal in CHTR have been simulated with ARCH-TH. The rising transient power in CHTR is being assumed to be arrested with temperature feedbacks in the core cooled with natural circulation of molten metal coolant LBE. The variation of several key parameters defining neutronics and thermal hydraulics of CHTR have been predicted and discussed in detail. It has been found that peak fuel and coolant temperatures are well within the safety limits during transient of inadvertent withdrawal of control rod in CHTR operating at full power during initial core life cycle

Evaluation of morphometric characteristics and watershed prioritization of Bhadar basin of Saurashtra region, Gujarat

Morphometric analysis is one of the important aspects of quantitative geomorphology which is primarily used to study the geometrical aspects of the landforms. The study was undertaken with the objectives of evaluating morphometric characteristic and prioritizing the watersheds of Bhadar basin based on its morphometric characteristics.  Linear, relief and aerial aspects were calculated for watershed characterization. The watersheds were ranked on the basis of high values of linear parameters and low values of shape parameters. A total of 16 watersheds 5G1B1, 5G1B2, 5G1B3, 5G1B4, 5G1B5, 5G1B6, 5G1B7, 5G1B8, 5G1B9, 5G1B10, 5G1B11, 5G1B12, 5G1B13, 5G1B14, 5G1B15 and 5G1B16 were identified in the Bhadar basin and morphometric characteristic of each watershed was determined. Highest priority indicated the greater degree of erosion in the particular watershed and it therefore priority should be given in applying soil conservation measures. It was concluded that the watershed 5G1B15 should be given highest priority because of higher erosion problems over other watersheds of Bhadar basin while 5G1B4 should be given the least priority

Comparative bioaccumulation potential of Pyxine cocoes and Bacidia submedialis in and around Faizabad city, Uttar Pradesh, India

Spatial trend in lichens diversity pattern with respect to pollution source provides vital information regarding environmental condition of the study area. In order to assess lichen diversity changes in one of the cultural centre of Uttar Pradesh, Faizabad city, lichen zone mapping technique was employed to observe spatial trends of lichen diversity in a grid of 1x1 km within 0-5,6-12 and 13-20 km distance from city centre in all the four directions. Overall 15 species were recorded from different directions. Among the different lichen species, Pyxine cocoes and Bacidia submedialis were common in most of the grids. Changes in physiological parameters and metal profile with respect to distance from city centre to the outskirts of the city in both P. cocoes and B. submedialis were analyzed. It was observed that the physiological parameters varied from site to site and in different directions, but the metal profile clearly indicates a decreasing trend of metal concentration with increasing distance from the city centre. The present study provides baseline data for future biomonitoring studies and further confirms the lichen biomonitoring study as an effective tool to monitor changes in environmental condition