Browsing by Author "Raghavendra, T."

Filter results by typing the first few letters
Now showing 1 - 5 of 5
  • No Thumbnail Available
    Item
    Effect of Water Content on Relative Flow Area and Hence Predicted Flow Values of Controlled Low Strength Materials
    (American Society of Civil Engineers (ASCE), 2018) Raghavendra, T.; Udayashankar, B.C.; Lokeshwari, M.; Shelar, M.; Amaranath Reddy, N.
    Urban cities are embracing new innovations in built-up spaces and thereby necessitating renovations or constructions for new buildings either by demolition of obsolete buildings or at new places to expand the city itself. In this regard natural stones are converted to aggregates and hence generate stone dust as a waste. Construction and demolition wastes include brickbats which are used as in-fills. Many attempts have been made to re-use these wastes but still the problem persists and large percentages of these wastes reach landfills. Controlled low strength materials (CLSM) are an obvious choice for use of these wastes in large quantities, required for sustainable city objectives. CLSM is a cementitious and self-flowing backfill material. Design of CLSM mixes involves iteration process mainly to satisfy the flow and strength requirements. Phenomenological models are an effective tool in the design of CLSM mixtures with a single trial. In this paper Class F fly ash was used as secondary cementitious material along with powdered brickbats, stone dust as fine aggregates in complete replacement to natural sand; to produce sustainable CLSM mixtures with varying Class F fly ash to cement ratios and water contents. Spread flow and marsh cone flow tests were conducted on fresh CLSM mixtures and compressive strength tests were carried out on hardened cylindrical specimens at 3, 7, 28, and 56 day age. Spread flow values were converted to relative flow area values. Phenomenological models (flow and strength) were generated using wide range of experimental data to predict flow and strength values. The water demand of quarry dust mixes was more compared to brickbats mixes and this resulted in lesser flow values and hence non-flow results. Incorporation of these non-flow values in the generation of flow prediction models resulted in poor prediction of flow results; however strength prediction was not influenced. Discarded brick bats and quarry dust are hence recommended for use as fine aggregates along with Class F fly ash as secondary cementitious material in CLSM to overcome urbanization challenge for sustainable development. © 2018 American Society of Civil Engineers.
  • No Thumbnail Available
    Item
    Optimizing machining responses of homologous TiNiCu shape memory alloys using hybrid ANN-GA approach
    (Elsevier Ltd, 2022) Roy, A.; Sachin, B.; Raghavendra, T.; Rao, C.M.; Naik, G.M.; Soni, H.; Mashinini, P.M.; Narendranath, S.
    Fabrication of shape memory alloys using wire electro discharge machining (WEDM) has gained popularity over the last few years. Most widely used machining parameters of WEDM process are pulse on time (Øon), pulse off time (Øoff), servo voltage (σ) and wire feed (ω). WEDM responses like material removal rate (MR), surface roughness (SR), kerf width (KW) and recast layer thickness (LT) have been evaluated by researchers to determine machining characteristics and are also considered for this study. These machining responses determine the quality of machining and are majorly influenced by thermal conductivity and melting temperature of the WEDM workpiece. Actuation behavior of shape memory alloys is a function of phase transformation characteristics which in turn depends on elemental composition of the selected alloys. Therefore, dissimilar machining responses of Ti50Ni40Cu10 and Ti50Ni25Cu25 have been observed even though similar machining input values were used. This study utilized artificial neural network (ANN) mapping to establish WEDM response function – which was used as fitness function to perform multi objective optimization using genetic algorithm (GA). It was found that ANN successfully predicted machining responses of selected homologous alloys and GA helped in identifying suitable input parameter values to optimize machining responses. © 2022
  • No Thumbnail Available
    Item
    Urbanization Challenges in Emerging Economies
    (American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2017) Mendi, V.; Reddy, N.A.; Lokeshwari, M.; Raghavendra, T.; Seelam, J.K.
    Tidal inlet is an opening along the coast which facilitates the exchange of water and nutrients. The energy extracted at the tidal inlet using tides is called tidal energy. Tidal energy is reliable and not depleting. Since the density of seawater is 800 times denser than air, the energy extraction is much favorable and reliable resource. Because of the above said advantages, tidal energy production has become an important energy source at global platform. The study area chosen is the Sri Lankan coast. The tidal condition along the Sri Lankan coast is semi diurnal. Identification of the locations for energy extraction is important as the width of the identified inlet at the coast plays an important role in energy extraction. Also, parameters like tidal range, basin area have to be taken into account in order to consider the inlet suitable for energy extraction. In this paper, tidal inlets will be identified along the Sri Lankan coast, the data will be collected for the parameters that are required to consider an inlet for energy extraction and the potential energy that can be extracted at the inlets will be assessed. © 2018 American Society of Civil Engineers.
  • No Thumbnail Available
    Item
    Urbanization Challenges in Emerging Economies
    (American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2017) Amarnatha Reddy, N.; Mendi, V.; Raghavendra, T.; Lokeshwari, M.
    The unit hydrograph (UH) concept needs observed rainfall-runoff data at the gauging site for hydrograph generation. But many catchments and watersheds in India are devoid of gauging stations and also it is not economically justifiable to collect the data and carry out detailed hydromorphological studies at every new site on a large scale. The paucity of such data sparked the idea of the synthetic unit hydrograph (SUH) concept. Most SUH procedures seek to establish relationships between parameters used to describe the UH and parameters used to describe the basin. In totality the available synthetic unit hydrograph methods/models have been classified into four groups as: traditional (or empirical), conceptual, probabilistic, and geomorphological. In the present study the probabilistic or probability distribution function (PDF) based methods/approaches are used to estimate the flood discharge at the ungauged basins in Varrar Basin at the coastal state of Kerala. The PDF based methods viz. Gray's method, Croley method, transmutation approach, and simplified gamma approach are used to develop UH at ungauged watersheds. The results of the total flood discharge at the ungauged basins are compared with volume of 1 cm direct runoff depth. © 2018 American Society of Civil Engineers.
  • No Thumbnail Available
    Item
    Urbanization Challenges in Emerging Economies
    (American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2017) Lokeshwari, M.; Mendi, V.; Raghavendra, T.; Reddy, A.; Udayashankar, B.C.
    Rapid urbanization, industrialization, and change of life style of people has increased the rate of solid waste generation by leaps and bounds in the developing countries. Municipal solid waste generation varies with place to place and the standard of living of the people residing in cities. Solid waste consists of organic matter, which undergoes degradation and produces foul smell, if not properly managed. Therefore management of the garbage had reached a very critical stage and now emphasis has been given to its collection, treatment, and final disposal. Generally in Indian cities, waste is collected and simply dumped outside the cities which are called as landfill sites. Any method of disposal other than composting will be uneconomical, required skilled person, and also pollute air, water, and soil. Large quantity of plant nutrients gets wasted in other methods of disposal. Composting is not a method of waste disposal but it is a method of recycling the waste. Municipal solid waste is one of the potential organic nutrient residues, which upon recycling leads to a valuable compost, which is vital for growth and development of plants. Sewage sludge is rich in micro-organisms, organic content, as well as nutrient elements. So in this study co-composting of municipal waste with sewage sludge has been taken up to conserve nutrients. In the present work studies were conducted on municipal solid waste, mixed with sewage sludge in different proportion, to check the technical viability of the integrated system of composting. Addition of sewage sludge to waste for composting not only increases decomposition rate and fertility value, it also solve the problem of sludge disposal from treatment plant. It will save the cost of sludge treatment. Municipal waste compost can be regarded as being valuable in soil management practices because of their organic matter content. © 2018 American Society of Civil Engineers.