Engaging with sustainability issues in metropolitan Chennai : city report

Chennai is the largest metropolitan city in South India (8.7 million in 2011) and the provincial capital of the large state of Tamil Nadu (population 72 million in 2011). Before that, under British rule, the city was the capital of the Madras Presidency, and was known as Madras until 1996, when the name was officially changed to Chennai. Located on the east coast of India, on the Bay of Bengal, sea trade has been an important aspect of the regional economy since at least the colonial period. Still today, the city combines political functions with economic command functions for both manufacturing and services, reflecting the region's diversified economy. The Chennai metropolitan area has witnessed strong growth over the last 20 years in automobile manufacturing, software services, hardware manufacturing, healthcare and financial services (CDP 2009). However, it should be noted that only 30% of total employment in the city takes place in the formal sector i.e., is covered by contracts and labour laws, the remaining 70% falls in the informal sector. This underscores the importance of small and micro enterprises and self-employment for providing goods, services and livelihoods in the local economy

Critical Review on Nanofluids: Preparation, Characterization, and Applications

Heat transfer fluids are a crucial parameter that affects the size and costs of heat exchangers. However, the available coolants like water and oils have low thermal conductivities, which put many limitations to the development of heat transfer to achieve high performance cooling. The need for development of new classes of fluids which enhance the heat transfer capabilities attracted the attention of many researchers. In the last few decades, modern nanotechnology developed nanoparticles, which have unique thermal and electrical properties that could help improve heat transfer using nanofluids. A “nanofluid” is a fluid with suspended fine nanoparticles which increases the heat transfer properties compared with the original fluid. Nanofluids are considered a new generation of heat transfer fluids and are considered two-phase fluids of liquid solid mixtures. The efficiency of the fluid could be improved by enhancing its thermal properties, especially the thermal conductivity, and it is expected that the nanofluids will have a greater thermal conductivity than the base fluids. This paper reviews the preparation of metallic and nonmetallic nanofluids along with the stability of the produced nanofluids. Physical and thermal properties as well as a range of applications are also discussed in detail

Thermal performance of stadium's Field of Play in hot climates

The stadium Field of Play (FoP) is a large area of grass that affects the stadiums overall thermal performance. This paper experimentally and numerically investigates the thermal performance of stadiums FoP in hot and arid climates. For a period of one year, the temperature readings of the FoP natural grass surface, subsoil at a depth of 200 mm and the surrounding running track were recorded for Khalifa stadium in Doha, Qatar. The temperature measurements were used to assess the accuracy of numerical predictions of the stadium FoP temperature distribution using two different numerical methods. First, a Direct Numerical Simulation (DNS) model was developed to simulate the unsteady heat transfer between the atmosphere and natural turf, and between the soil and turf. The DNS model accounts for radiative, convective, conductive and evaporating heat on the surface for different climates. Second, a prognostic three-dimensional ENVI-met climate model was utilized to simulate the stadium FoP microclimate system. Although the measured and simulated data showed good agreement, differences were noticed at the peak temperatures. In winter and spring seasons, the peak temperature predicted by the DNS model appeared one hour later than the measured peak temperature, while the ENVI-met predicted peak temperature was detected two hours later. The difference is attributed to the treatment of soil thermal capacity and its water content. Both of the numerical models considered the soil temperature as constant near the averaged measured soil data. For the grass surface and subsoil, the DNS model could better predict the temperature change during the day of the four seasons. The research results can be utilized to validate the thermal models proposed to simulate stadiums thermal performance.Scopu

Engaging with Sustainability Issues. In Metropolitan Chennai, City report series

Publication en ligne, City report series (Chance2Sustain