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Stainless steels have received wide attention as a substitute material for bipolar plates in high temperature proton exchange membrane fuel cell (HT-PEMFC). In the present work, the CrN, CrAlN and multilayer CrN/CrAlN coatings were deposited on 316L SS to increase the corrosion resistance and decrease the interfacial contact resistance. The deposited coatings exhibited face centered cubic phase structure and it was verified from the X-ray diffraction pattern. X-ray photo electron spectroscopy results showed the formation of both CrN and CrAlN layers on 316L SS. CrN/CrAlN coating is more helpful in water management due to low surface roughness and high contact angle in the HT-PEMFC environment. The corrosion resistance behavior of all the samples were studied in 85% H3PO4 solution at 140 °C purged with H2 (HT-PEMFC anode) and O2 (HT-PEMFC cathode) gases. The results showed that all the coatings considerably improved the performance of 316L SS and superior corrosion resistance was observed for CrN/CrAlN multilayer coating, whose protective efficiency was 98.12% and 96.14% in the two simulated HT-PEMFC environments. The results of electrochemical impedance spectroscopic studies demonstrated higher impedance for CrN/CrAlN coating. Surface morphological studies performed after corrosion studies revealed that protection ability of CrN/CrAlN coating still remained acceptable. A very low interfacial contact resistance value of 6 mΩ cm2 at 140 N/cm2 was observed for CrN/CrAlN coating. Moreover, after corrosion studies, the interfacial contact resistance value of CrN/CrAlN coated 316L was much lower than that of CrN and CrAlN coatings due to the increased oxidation resistance. The maximum power density of about 0.93 W/cm2 at 2 A/cm2 and output voltage of 0.96 V was observed for CrN/CrAlN coating.

The single layers of TiN, TiAlN and TiN/TiAlN multilayer coatings were deposited on 316L SS bipolar plate by physical vapor deposition technique. The X-ray diffraction studies revealed that the formed coatings exhibited single-phase cubic structure. The low surface roughness and high contact angles of the TiAlN and TiN/TiAlN coatings governed the better water management in the fuel cell. Nyquist and Bode-impedance studies of TiN/TiAlN coating ensured higher electrochemical impedance behavior. The polarization results revealed that the current densities (icorr) of TiN/TiAlN coating were below 1 µA/cm2 in the PEMFC environments, which satisfied the U.S. Department of Energy’s 2020 target. The contact resistance of the TiN/TiAlN-coated 316L SS was the lowest and fulfilled the requirements of bipolar plate (≤ 10 mΩ cm2) in PEMFC environment. Surface morphology results revealed that the surface of 316L SS is well protected by multilayer TiN/TiAlN coating. Inductive coupled plasma-optical emission spectroscopy results are in good agreement with electrochemical studies revealing the TiN/TiAlN coating significantly reduced the metal ions dissolution.

The present investigation is about the economic analysis of the hook and line fishery along the coast of Kombuthurai, Thoothukudi district of Tamil Nadu. Inferences from the study indicated that that hook number 5, 6 and 7 were found ideal for commercial exploitation of Carangids, Grouper, Barracuda and Needlefish in angling by wielding fresh condition live bait. Using the artificial lure number 3.5, 4.0 and 4.5 applied in trolling line, the most dominant catch was seer fish (80%) and least in sailfish (8%). Significantly the study reports that the highest gross revenue ₹42060/trip was made in trolling line than that of the handline of ₹26400/trip ascribed by targeted of high market value species. The trolling line crew share per person was twice over than the handline fishing (₹3821/trip). Instead of unorthodox eye estimation of fish weight, a novel approach of weight based fish sale (for low to high market value species) was observed in Kombuthurai fishing village and this practiced also espoused by a neighbor fishing village.

In present study attempts has been made to document the fishing crafts and gears which operated in Thirumoorthy reservoir, Tamil Nadu. This investigation revealed, the post monsoon season had higher catch per unit effort of 11kg/boat/day by gillnet fishing and about 20 to 30kg/day in cast net. Catla catla has the dominant fish species and accounted about 58% followed by Cirrhinus mrigala (29%), Labeo rohita (12%) and Cyprinus carpio (2%) against the total landings. However, three species including the Tilapia, Rohu and Mrigala were found to constitute fishery in the cast net with mean CPUE of 20 to 30 kg per day.

The main objective of the study is to quantify the mass concentration exposure levels of fine traffic-generated particles (PM2.5) at various heights of typical multi-storey public housing buildings located in close proximity, i.e. within 30 m and along a busy major expressway in Singapore. The secondary objective is to compare the potential health risks of occupants in the buildings, associated with inhalation exposure of fine traffic-generated particulate matter, based on estimated dose rates and the lowest observed adverse effect levels (loael) at the various floors of these buildings. Two typical public housing buildings, both naturally ventilated residential apartment blocks, of point block configuration (22-storey) and slab block configuration (16-storey) were selected for the study. Particulate samples were collected for both mass and chemical analysis (OC/EC ratio) at three representative floors: the lower, the mid, and upper floors of the buildings. Key meteorological parameters such as wind speed, wind direction, ambient temperature, and relative humidity were also concurrently measured at the sampling locations. For the potential health risk analysis, the occupants have been divided into four age categories namely, infants, children (1 year), children (8–10 years) and adults. The analysis takes into account age-specific breathing rates, body weights for different age categories. Experimental results explicitly showed that PM2.5 mean particle mass concentration was highest at the midfloors of both buildings when compared to those measured at upper and lower floors during a typical day. Although the lower floors were closest to traffic emissions, the mean particle mass concentration was lower there than that at the midfloors, which could presumably be due to the interception of PM2.5 particles by tree leaves or the inflow of clean and drier air from higher altitude with lower aerosol burden mixing with the traffic-polluted air at the lower levels thus lowering the concentration at the lower floors similar to induced chimney effect or both. The upper floors had the least fine particulate matter mass concentration due to dilution following pronounced mixing of traffic-polluted air with ambient air. The only difference between both blocks is that at corresponding floors, the mass concentration levels for slab block is much higher than that of point block. This could be attributed to the configuration of the blocks. Observational data show the slab block tends to slow down the approaching wind thus allowing the accumulation of the fine traffic-generated particulate matter in front of the building. For point block, the HR values at the mid and lower floors suggest that occupants living in these floors experience 1.81 and 1.34 times more health risk, respectively, in contracting respiratory diseases when compared to those living at the upper floors for all age categories. Similarly, for the slab block, occupants living in the mid and lower floors had 1.62 and 1.28 times more risk, respectively, in contracting respiratory diseases when compared to those living at the upper floors for all age categories.

The main objective of the study is to quantify the polycyclic aromatic hydrocarbons (PAHs) concentration levels (US EPA priority components) in fine traffic-generated particles (PM2.5) at various heights of typical multi-storey public housing buildings located in close proximity, i.e. within 30 m and along a busy major expressway in Singapore. The secondary objective is to estimate the potential health risks associated with inhalation exposure, based on the toxic equivalency factors (TEFs) at the various floors of these buildings. Two typical public housing buildings, both naturally ventilated residential apartment blocks, of point block configuration (22-storey) and slab block configuration (16-storey) were selected for the study. Particulate samples were collected for chemical analysis at three representative floors: the lower, the mid, and the upper floors of the buildings. Key meteorological parameters such as wind speed, wind direction, ambient temperature, and relative humidity were also measured at the representative floors. All samples were analyzed for the 16 PAH priority pollutants listed by US EPA. The vertical PAH distribution profile varies with height of building depending on the type of block configuration. The total mean concentrations of particulate PAHs for point and slab blocks are 3.32±1.76 ng/m3 (0.56–7.2 ng/m3) and 6.0±1.88 ng/m3 (3.19–10.26 ng/m3), respectively. For the point block, the highest mean total PAH concentration occurred at the mid floor followed by the upper floor. The lower floor had the least mean total PAH concentration. For the slab block, the highest mean total PAH concentration occurred at the lower floor and remained almost constant up to the mid floor and thereafter gradually decreased from mid floor to upper floor of the building. These results suggest that the building configuration influences the vertical distribution of particulate PAHs. The dominant particulate PAHs measured at the point block are naphthalene, acenaphthylene, benzo(b)fluoranthene, and benzo(g,h,i)perylene while those for the slab block, the main particulate PAHs are naphthalene, phenanthrene, fluoranthene, and benzo(g,h,i)perylene. The Bpe/Ind ratio for both blocks ranged from 0.92±0.2 to 1.63±0.6 indicating particulate PAHs are contributed by a mixture of both diesel and petrol engine type of vehicles, with diesel engine vehicles contributing a higher percentage of particulate PAHs to the different floor levels of both buildings. The total BaPeq concentrations for point and slab blocks are 1.06±0.64 ng/m3 (0.14–2.45 ng/m3) and 0.94±1.22 ng/m3 (0.10–4.59 ng/m3), respectively. The total BaP equivalency results showed the potential health risk to cancer due to inhalation exposure is of concern for residents living in both blocks since the total BaPeq concentrations for both blocks were very close to, or slightly exceeded the maximum permissible risk level of 1 ng/m3 of benzo(a)pyrene.

The aim of the study is to perform a potential health risk assessment on children in contracting respiratory symptoms due to inhaling traffic-generated nitrogen dioxide (NO2) in two typical high-rise naturally-ventilated residential building designs (slab and point block) located close to busy major expressways in a tropical climate. A total of six buildings were selected for the study. Ogawa passive samplers (PS-100) were used for NO2 measurements in each building over a period of 5 weeks during the predominant monsoon seasons. Health risk assessment showed children residing at the mid floors of the buildings had the highest health risk regardless of their age .i.e. infants, children (1 year and under), children (8-10 years)compared to those residents residing at the high and low floors. This was expected since the highest concentration of traffic-generated NO2 concentration occurred at the mid floors of the buildings. In a typical floor, children (1 year and under) had the highest followed by children (8-10 years) whilst new born infants had the least potential health risk in contracting respiratory symptoms. The reason might could be new born infants obtain passive immunity from their mothers and in children (1 year and under), the passive immunity fall during this age period as they are developing their very own immunity against respiratory symptoms. Children (8-10 years) had the their potential health risk to respiratory symptoms in between the other two age groups as these children could have developed more immunity against respiratory symptoms compared to the children (1 year and under) but less immunity compared to infants. Based on the mean overall HR values, children living in a slab block has about 1.27 times more risk in contracting a respiratory symptoms due to NO2 inhalation compared to those living in a point block.

Air pollution has become a subject of great interest on the global scale from both the regulatory and the scientific points of view. This is a result of the expanding economies, increasing population and urbanization. Particulate matter pollution has become a serious concern in urban areas due to its adverse impacts on human health (US EPA 2009). Most of the previous studies reported in the literature on particulate air pollution deal with its temporal and spatial distributions as part of routine air quality monitoring (Hitchins et al. 2000; Wu et al. 2002; Levy et al. 2003; Morawska et al. 1999; Zhu et al. 2002), but little work has been done on its vertical distribution in the vicinity of buildings. The horizontal distribution of particles is of interest because it helps town planners to decide on the location of buildings and amenities considering the degree of exposure of occupants to fine and ultra fine particles. In addition to those studies, the vertical distribution of particles also merits consideration because it provides an understanding how particles are distributed with respect to the height of a building so that one can decide on the location of the natural air intake of the building, or the building orientation based on the source of particulate matter pollution.