Are Galaxies Optically Thin to Their Own Lyman Continuum Radiation? II. NGC 6822

Halpha and UBV photometry of NGC 6822 are used to study the distribution of OB stars and HII regions in the galaxy and to determine whether individual regions of the galaxy are in a state of ionization balance. Four distinct components of the Halpha emission (bright, halo, diffuse and field) differentiated by their surface brightnesses are identified. We find that approximately 1/2 of all OB stars in NGC 6822 are located in the field while only 1/4 are found in the combined bright and halo regions, suggesting that OB stars spend roughly 3/4 of their lifetimes outside ``classical'' H II regions. Comparing the observed Halpha emission with that predicted from stellar ionizing flux models, we find that although the bright, halo and diffuse regions are probably in ionization balance, the field region is producing at least 6 times as much ionizing flux as is observed. The ionization balance results in NGC 6822 suggest that star formation rates obtained from Halpha luminosities must underestimate the true star formation rate in this galaxy by about 50%. Comparing our results for NGC 6822 with previous results for the spiral galaxy M33, we find that the inner kiloparsec of M33 is in a more serious state of ionization imbalance, perhaps due to its higher surface density of blue stars.Comment: Replaced version should now compile with standard aastex style files. 28 pages, aastex preprint format. Accepted in ApJ. Hardcopies of figures available on request to [email protected]

Theoretical face pressure and drag characteristics of forward-facing steps in supersonic turbulent boundary layers

A theoretical investigation of the pressure distributions and drag characteristics was made for forward facing steps in turbulent flow at supersonic speeds. An approximate solution technique proposed by Uebelhack has been modified and extended to obtain a more consistent numerical procedure. A comparison of theoretical calculations with experimental data generally indicated good agreement over the experimentally available range of ratios of step height to boundary layer thickness from 7 to 0.05

An experimental and theoretical study of the flow phenomena within a vortex sink rate sensor

Tests were conducted to obtain a description of the flow field within a vortex sink rate sensor and to observe the influence of viscous effects on its performance. The characteristics of the sensor are described. The method for conducting the test is reported. It was determined that for a specific mass flow rate and the geometry of the vortex chamber, the flow in the vortex chamber was only affected, locally, by the size of the sink tube diameter. Within the sink tube, all three velocity components were found to be higher for the small sink tube diameters. As the speed of rotation of the sensor was increased, the tangential velocities within the vortex chamber, as well as in the sink tube, increased in proportion to the speed of rotation

Urban heritage conservation and rapid urbanization : insights from Surat, India

Currently, heritage is challenged in the Indian city of Surat due to diverse pressures,  including rapid urbanization, increasing housing demand, and socio‐cultural and climate changes.  Where rapid demographic growth of urban areas is happening, heritage is disappearing at an  alarming rate. Despite some efforts from the local government, urban cultural heritage is being  neglected and historic buildings keep being replaced by ordinary concrete buildings at a worryingly  rapid pace. Discussions of challenges and issues of Surat’s urban area is supported by a qualitative  dataset, including in‐depth semi‐structured interviews and focus groups with local policy makers,  planners, and heritage experts, triangulated by observation and a photo‐survey of two historic  areas. Findings from this study reveal a myriad of challenges such as: inadequacy of urban  conservation management policies and processes focused on heritage, absence of skills, training,  and resources amongst decision makers and persistent conflict and competition between heritage  conservation needs and developers’ interests. Furthermore, the values and significance of Surat’s  tangible and intangible heritage is not fully recognized by its citizens and heritage stakeholders. A  crucial opportunity exists for Surat to maximize the potential of heritage and reinforce urban  identity for its present and future generations. Surat’s context is representative of general trends  and conservation challenges and therefore recommendations developed in this study hold the  potential to offer interesting insights to the wider planners and conservationists’ international  community.  This  paper  recommends  thoughtful  integration  of  sustainable  heritage  urban  conservation into local urban development frameworks and the establishment of approaches that  recognize the plurality of heritage values

Study on medicinal plants with special reference to family Asteraceae, Fabaceae and Solanaceae in G.G.V-Campus, Bilaspur (C. G.) in central India.

Present study deals with the study on mportant Medicinal plants diversity and documentation in G. G. V. – (A Central University) Bilaspur (C. G.). Many of the Medicinal plants have been recorded. Out of them a total number 36 species belonging to the family Asteraceae, Fabaceae and Solanaceae were listed. 10 species of Asteraceae, 17 species of family Fabaceae and 09 species of Solanacceae were observed. Highest percentage distribution of the plants shown by the family Fabaceae, whereas among three targeted families Solanaceae registered minimum % distribution in the university campus. After survey of area Medicinal plants were collected and categorized based on their related family and further scientific informations like Botanical name, Family, Habit, Parts used, Phyto-chemicals, Use and Propagation were noticed following literatures. The recorded data on Medicinal flora are listed in Tables and discussed furthermore

Colocasia esculanta Linn : Cultivation in Dabhara block in Janjgir – Champa district, Chhattisgarh in central India

Colocasia esculanta Linn. is an annual herbaceous plant with small corms in side of the soil. All the plant parts are used as vegetable as well as medicinal purpose among the rural peoples. It is also a source of economic increment to the farmers. The study based on the assessing the cultivation of the Colocasia esculanta Linn. in Janjgir – Champa district of central part of Chhattisgarh state. The plant is also referred as a commercial crop. Many flavonoides and steroids have been isolated from Colocasia esculanta Linn. The plant is grown in India for especially its corm, leaves etc. India is marked as a center of origin of this plant. Plant produces more corms in sandy-black soil but capable to grow in all type of the soil, so it is cultivated over the state. During cultivation Well soil preparation, fertilizers, weed, disease etc. management is required. Out of them well water discharge from cultivated field play a key role for successful growth and development of the plant.The present paper focused on the cultivation and use of the Colocasia esculanta Linn in the Study area