1,946 research outputs found
An HI perspective on galaxies 2.5 billion years ago
Galaxies are believed to have formed and evolved within clumps of dark matter (known as dark matter halos) through the merging of smaller, less complex systems, as explained by one of the most popular cosmological models known as Lambda CDM (ΛCDM). Thus, the properties of galaxies are shaped by their genesis (nature) and the influence of the environments in which they reside (nurture). Synergizing our knowledge of stellar population studies with the gas content of galaxies provides a more complete picture of how galaxies we see today evolved over time. In particular, the atomic hydrogen content of galaxies (HI) is a vital ingredient in star formation and provides unparalleled insights into the role of gas and environment in galaxy evolution. Unfortunately, not much is known about the behaviour of HI over cosmic time due to limitations in telescope sensitivity for deep HI observations.In this thesis, we presented the data and results of the Blind Ultra-Deep HI Environmental Survey (BUDHIES), which still provides some of the only blind observations of 166 galaxies detected over a range of cosmic environments at a redshift z~0.2 (~2.5 billion years in look-back time). this thesis also provides further insights into the time evolution of HI in galaxies using tools such as the HI mass function and the Tully-Fisher relation, along with the details on the data processing and optical counterpart identification with ancillary data. This thesis aims to provide a benchmark for next-generation HI surveys that will be able to overcome the limitations of current radio facilities
Phenol degradation using 20, 300 and 520 kHz ultrasonic reactors with hydrogen peroxide, ozone and zero valent metals
The extent of phenol degradation by the advanced oxidation process in the presence of zero valent iron (ZVI) and zero valent copper (ZVC) was studied using 20, 300 and 520 kHz ultrasonic (US) reactors. Quantification of hydrogen peroxide has also been performed with an aim of investigating the efficacy of different sonochemical reactors for hydroxyl radical production. It has been observed that the 300 kHz sonochemical reactor has the maximum efficacy for hydroxyl radical production. Phenol degradation studies clearly indicate that degradation of phenol is intensified in the presence of the catalyst and hydrogen peroxide, which can be attributed to enhanced production of hydroxyl radicals in the system. Experimental data shows that with ZVI, when the reaction was subjected to 300 kHz, complete phenol removal and 37% TOC mineralization was achieved within 25 min, whereas, in the case of 20 kHz US treatment no phenol was detected after 45 min and 39% TOC mineralization was observed. This novel study also investigated the use of zero valent copper (ZVC) and results showed that with 20, 300 and 520 kHz ultrasonic rectors, phenol removal was 10–98%, however, the maximum TOC mineralization achieved was only 26%. A comparative study between hydrogen peroxide and ozone as a suitable oxidant for Fenton-like reactions in conjunction with zero valent catalysts showed that an integrated approach of US/Air/ZVC/H2O2 system works better than US/ZVC/O3 (the ZOO process)
Intensification of hydroxyl radical production in sonochemical reactors
The efficacy of sonochemical reactors in chemical processing applications has been well established in the laboratory scale of operation though at a given set of operating parameters and no efforts have been directed in terms of maximizing the free radical production. In the present work, the effect of different operating parameters viz. pH, power dissipation into the system, effect of additives such as air, haloalkanes, titanium dioxide, iron and oxygen on the extent of hydroxyl radical formation in a sonochemical reactor have been investigated using salicylic acid dosimetry. Possible mechanisms for oxidation of salicylic acid in the presence of different additives have also been established. It has been observed that acidic conditions under optimized power dissipation in the presence of iron powder and oxygen result in maximum liberation of hydroxyl radicals as quantified by the kinetic rate constant for production of 2,5- and 2,3-dihydroxybenzoic acid. The study has enabled the optimization of the conditions for maximum efficacy of sonochemical reactors where free radical attack is the controlling mechanism for the chemical processing applications
The Revampa Lamp- An Interactive Lighting System that bridges the Gap between Aesthetics and Function within the Interior
This system of lighting has been produced for the “architecture of flavours” expo to be hosted on the 19th of April, 2016. My brief entailed producing lighting for 12 dinner tables that the invitees could interact with. The design is meant to stem from the menu that showcases food inspired from the “flavours” of three buildings as conceived by members of the graduating class of 2016 (shown below). The organisers of this event also want their guests to take an experience away from the evening, and have tasked me with making this idea come to fruition literally
A Note on Ultra-Short Waves and Radiation from Free Electrons.
It deals with the Ultra-Short Waves and Radiation from Free Electrons
- …