CO2 fixation by seaweeds and their role in De-acidifying Ocean - An experimental approach

CO2 fixation by seaweeds and their role in De-acidifying Ocean - An experimental approac

Role of seaweeds in neutralizing the impact of seawater acidification- A laboratory study with beached shells of certain bivalves and spines of a sea urchin

Ocean acidification is one of the major impacts of climate change in sea which is manifested by the decrease in hydrogen ion concentration (pH) of seawater mainly due to increased uptake of CO2 and reduction in carbonate ions. This is a report on the dissolution rate of dead shells of four marine bivalves and spines of a sea urchin when treated with different levels of CO2 dissolved in seawater for 48 hours which was measured gravimetrically. Dissolution of dead shells expressed as reduction in shell weight was directly proportional to the concentration of dissolved CO2. Live thallus of green seaweed Chaetomorpha antennina did reduce the magnitude of dissolution rates (P<0.05) of all the shells and spines considerably as well as the change in pH of ambient seawater due to the addition of CO2. The remedial property of seaweeds was more effective at lower concentrations of dissolved CO2. The induced change in pH was restored by green seaweed only at concentrations above 250 ppm. Although we noticed strong impact of dissolved CO2 on the dead shells of Mactrinula plicataria even at 100 ppm level, the remedial action by the green seaweed was maximum in Siliqua radiata followed by Perna viridis. Results of this laboratory study shows the positive role of seaweeds in neutralizing the acidification impacts

Not Available

Not AvailableOcean acidification is one of the major impacts of climate change in sea which is manifested by the decrease in hydrogen ion concentration (pH) of seawater mainly due to increased uptake of CO2 and reduction in carbonate ions. This is a report on the dissolution rate of dead shells of four marine bivalves and spines of a sea urchin when treated with different levels of CO2 dissolved in seawater for 48 hours which was measured gravimetrically. Dissolution of dead shells expressed as reduction in shell weight was directly proportional to the concentration of dissolved CO2. Live thallus of green seaweed Chaetomorpha antennina did reduce the magnitude of dissolution rates (P<0.05) of all the shells and spines considerably as well as the change in pH of ambient seawater due to the addition of CO2. The remedial property of seaweeds was more effective at lower concentrations of dissolved CO2. The induced change in pH was restored by green seaweed only at concentrations above 250 ppm. Although we noticed strong impact of dissolved CO2 on the dead shells of Mactrinula plicataria even at 100 ppm level, the remedial action by the green seaweed was maximum in Siliqua radiata followed by Perna viridis. Results of this laboratory study shows the positive role of seaweeds in neutralizing the acidification impacts.Not Availabl

Effects of reflow profile and miniaturisation on integrity of solder joints in surface mount chip resistor

Integrity of solder joints of components in an electronic device is critical to the device reliability. Miniaturisation manufacturing trend in electronic products development has continued to challenge the shear strength of the solder joints in these devices and necessitates implementation of optimal reflow profile to achieve maximum strength of the joints. This research proposes optimal parameter combination of reflow profile factors which demonstrate potential of delivering maximum shear strength of solder joint. The Taguchi design of experiment (DoE) is employed to generate eight orthogonal array designs of L24 of reflow profiles. The factors/parameters investigated are preheat gradient, time above liquidus (TAL), peak temperature and cooling rate. Three test vehicles of varying solder joint sizes are made from R1206, R0805 and R0603 resistors. Reflow profile number 3 constituting 1.2 °C/s preheat, 45 s TAL, 245 °C peak temperature and 60% cooling rate is optimal because it yielded joints with highest strength and circa 4 µm thickness of intermetallic compound (IMC). Solder joint shear strength decreases with decrease in size of lead-free joint irrespective of reflow profile implemented. These results will be useful to electronic packaging and reliability engineers faced with challenges of improving device operational mechanical performance in the continuing product miniaturisation trend