Contribution of sewage treatment to pollution abatement of urban streams

In this study, we assessed the efficiency and effectiveness of the Vrishabhavathy Valley Treatment plant (VVTP) in Bengaluru city, which is the oldest STP in the city. Since VVTP treats both raw sewage and polluted river water, with the latter constituting 80% of the influent, we sampled water quality at locations upstream and downstream of the plant to evaluate overall efficacy as well

Evaluation of Noise Radiation Mechanisms in Turbulent Jets

Data from the direct numerical simulation (DNS) of a turbulent, compressible (Mach = 1.92) jet has been analyzed to investigate the process of sound generation. The overall goals are to understand how the different scales of turbulence contribute to the acoustic field, and to understand the role that linear instability waves play in the noise produced by supersonic turbulent jets. Lighthill’s acoustic analogy was used to predict the radiate sound from turbulent source terms computed from the DNS data. Preliminary computations (for the axisymmetric mode of the acoustic field) showgood agreement between the acoustic field determined from DNS and acoustic analogy. Further work is needed to refine the calculations and investigate the source terms. Work was also begun to test the validity of linear stability wave models of sound generation in supersonic jets. An adjoint-based method was developed to project the DNS data onto the most unstable linear stability mode at different streamwise positions. This will allow the evolution of the wave and its radiated acoustic field, determined by solving the linear equations, to be compared directly with the evolution of the near and far-field fluctuations in the DNS

Influence of crystallite shape on particle size broadening of Debye-Scherrer reflections

Formulae for the Scherrer constant Kβ, the variance Scherrer constant Kω and the taper parameter Lω for crystals having the external shapes of a triangular prism, a square prism, a hexagonal prism and a cylinder have been obtained in terms of the reflection indices and proportionality factors,viz., the ratio of the height of the crystal to the square root of its basal area and the ratio of the two lattice constants of the unit cell. The numerical values of Kβ, Kω and Lω have also been computed for direct application in particular cases

Water Management in Arkavathy basin: a situation analysis

The Arkavathy sub-basin, which is part of the Cauvery basin, is a highly stressed, rapidly urbanising watershed on the outskirts of the city of Bengaluru. The purpose of this situation analysis document is to summarise the current state of knowledge on water management in the Arkavathy sub-basin and identify critical knowledge gaps to inform future researchers in the basin. It is hoped that such an analysis will help those studying or working on water issues in the basin itself, and also provide useful insights for other such urbanising basins. The Arkavathy sub-basin is located in the state of Karnataka in India (see Figure 1). It covers an area of 4,253 km2, and is part of the inter-state Cauvery River basin. The sub-basin covers parts of eight taluka – Doddaballapur, Nelamangala, Magadi, Bangalore North, Bangalore South, Ramanagara, Anekal and Kanakapura within three districts – Bangalore Urban, Bangalore Rural and Ramanagara. The total population in the sub-basin was 72 lakhs in 2001 and is estimated to be approximately 86 lakhs in 2011. This is distributed approximately 50:50 between urban and rural settlements (although the urban share is growing rapidly), with 33 lakhs from Bengaluru city (more than one-third of Bengaluru’s total population). There are also four major Class II towns: Doddaballapur, Nelamangala, Ramanagara, and Kanakapura with populations ranging from 35,000 to 95,000. In spite of rapid urbanisation, there are still 1,107 revenue villages with populations ranging from less than 10 to 6,0001, and agriculture continues to be the mainstay of a large number of them

Modeling intermittent wavepackets and their radiated sound in a turbulent jet

We use data from a new, carefully validated, Large Eddy Simulation (LES) to investigate and model subsonic, turbulent, jet noise. Motivated by the observation that sound-source dynamics are dominated by instability waves (wavepackets), we examine mechanisms by which their intermittency can amplify their noise radiation. Two scenarios, both involving wavepacket evolution on time-dependent base flows, are investigated. In the first, we consider that the main effect of the changing base flow consists in different wavepacket ensembles seeing different steady mean fields, and having, accordingly, different acoustic efficiencies. In the second, the details of the base-flow time dependence also play a role in wavepacket sound production. Both short-time-averaged and slowly varying base flows are extracted from the LES data and used in conjunction with linearized wavepacket models, namely, the Parabolized Stability Equations (PSE), the One-Way Euler Equations (OWE), and the Linearized Euler Equations (LEE). All results support the hypothesized mechanism: wavepackets on time-varying base flows produce sound radiation that is enhanced by as much as 20dB in comparison to their long-time-averaged counterparts, and ensembles of wavepackets based on short-time-averaged base flows display similar amplification. This is not, however, sufficient to explain the sound levels observed in the LES and experiments. Further work is therefore necessary to incorporate two additional factors in the linear models, body forcing by turbulence and realistic inflow forcing, both of which have been identified as potentially important in producing the observed radiation efficiency

Direct force probe reveals the mechanics of nuclear homeostasis in the mammalian cell

How cells maintain nuclear shape and position against various intracellular and extracellular forces is not well understood, although defects in nuclear mechanical homeostasis are associated with a variety of human diseases. We estimated the force required to displace and deform the nucleus in adherent living cells with a technique to locally pull the nuclear surface. A minimum pulling force of a few nanonewtons--far greater than typical intracellular motor forces--was required to significantly displace and deform the nucleus. Upon force removal, the original shape and position were restored quickly within a few seconds. This stiff, elastic response required the presence of vimentin, lamin A/C, and SUN (Sad1p, UNC-84)-domain protein linkages, but not F-actin or microtubules. Although F-actin and microtubules are known to exert mechanical forces on the nuclear surface through molecular motor activity, we conclude that the intermediate filament networks maintain nuclear mechanical homeostasis against localized forces

Cross-View Action Recognition from Temporal Self-Similarities

This paper concerns recognition of human actions under view changes. We explore self-similarities of action sequences over time and observe the striking stability of such measures across views. Building upon this key observation we develop an action descriptor that captures the structure of temporal similarities and dissimilarities within an action sequence. Despite this descriptor not being strictly view-invariant, we provide intuition and experimental validation demonstrating the high stability of self-similarities under view changes. Self-similarity descriptors are also shown stable under action variations within a class as well as discriminative for action recognition. Interestingly, self-similarities computed from different image features possess similar properties and can be used in a complementary fashion. Our method is simple and requires neither structure recovery nor multi-view correspondence estimation. Instead, it relies on weak geometric cues captured by self-similarities and combines them with machine learning for efficient cross-view action recognition. The method is validated on three public datasets, it has similar or superior performance compared to related methods and it performs well even in extreme conditions such as when recognizing actions from top views while using side views for training only