Streamlined vessels for speedboats: Macro modifications of shark skin design applications

Functional properties of shark denticles have caught the attention of engineers and scientist today due to the hydrodynamic effects of its skin surface roughness. The skin of a fast swimming shark reveals riblet structures that help to reduce skin friction drag, shear stresses, making its movement to be more efficient and faster. Inspired by the structure of the shark skin denticles, our team has conducted a study on alternative on improving the hydrodynamic design of marine vessels by applying the simplified version of shark skin skin denticles on the surface hull of the vessels. Models used for this study are constructed and computational fluid dynamic (CFD) simulations are then carried out to predict the effectiveness of the hydrodynamic effects of the biomimetic shark skins on those models. Interestingly, the numerical calculated results obtained shows that the presence of biomimetic shark skin implemented on the vessels give improvements in the maximum speed as well as reducing the drag force experience by the vessels. The pattern of the wave generated post cruising area behind the vessels can also be observed to reduce the wakes and eddies. Theoretically, reduction of drag force provides a more efficient vessel with a better cruising speed. To further improve on this study, the authors are now actively arranging an experimental procedure in order to verify the numerical results obtained by CFD. The experimental test will be carried out using an 8 metre flow channel provided by University Malaysia Sarawak, Malaysia. © 2018 Author(s)

Air flow optimization for energy efficient blower of biosafety cabinet class II A2

An energy efficient Biosafety Cabinet (BSC) has become a big challenge for manufacturers to develop BSC with the highest level of protection. The objective of research is to increase air flow velocity discharge from centrifugal blower. An aerodynamic duct shape inspired by the shape of Peregrine Falcon's wing during diving flight is added to the end of the centrifugal blower. Investigation of air movement is determined by computational fluid dynamics (CFD) simulation. The results showed that air velocity can be increased by double compared to typical manufactured BSC and no air recirculation. As conclusion, a novel design of aerodynamic duct shape successfully developed and proved that air velocity can be increase naturally with same impeller speed. It can contribute in increasing energy efficiency of the centrifugal blower. It is vital to BSC manufacturer and can be apply to Heating, Air Ventilation and Air Conditioning (HVAC) industries. © Published under licence by IOP Publishing Ltd

Optimisation of Remazol Brilliant Blue R dye decolourisation and laccase enzyme production by Marasmius cladophyllus using response surface methodology

The decolourisation of Remazol Brilliant Blue R dye and laccase activity was investigated using pure culture of an endophytic fungus, Marasmius cladophyllus. The fungus is found capable of decolourising 99% of the dye after 12 days of incubation in Glucose Minimal (GM) liquid media (pH 5.5) and laccase activity of 285 U/L was recorded. Response surface methodology (RSM) was used to determine and optimise the significant variable(s) in order to obtain the optimum dye decolourisation conditions and laccase production. It was also used to study the interaction effect of the variables on both responses. Box-Behnken Design was used to identify the significant variable(s) whereas the optimisation process was done by using Central Composite Design. It was found that initial dye concentration of 100-300 mg/L, incubation period of 4-20 days and pH of liquid medium of 4-8 significantly influenced the decolourisation of dye and laccase activity. However, only the relationship of the incubation period and pH is significantly affected both the responses. Maximum dye decolourisation of 100% was successfully achieved and the highest laccase activity of 504.53 U/L was recorded after 16 days of incubation period at pH 7 with 259.46 mg/L initial dye concentration

The degradation of carbazole and the production of ligninolytic enzyme by isolated marine fungi

Biodegradation of carbazole heterocyclic hydrocarbon by isolated marine fungi were tested. Out of the 64 fungal isolates tested, 5 fungi were able to decolorize more than 50% of 0.01% Remazol Brilliant Blue R. Isolate B3 were able to decolorize 99% of RBBR in all concentrations tested. Isolate B3 and B4 showed the highest removal of carbazole at 88% and 53%, respectively as observed with GCMS in the degradation trial. Laccase enzyme was produced in high concentration of 528.00±11.33 U/L and 642.67±11.43 U/L for isolate B3 and B4. It is observed that the presence of carbazole triggered the production of laccase as it was produced only at 106.67±3.33 U/L and 14.00 U/L for isolate B3 and B4 without carbazole. Results suggested that isolate B3 belonged to the Basidiomycota. The prospects of carbazole biodegradation by these isolates are suspected to be contributed through the production of laccase (Lac)

Biodegradation of phenol by cold-adapted bacteria from Antarctic soils

Phenol is an important pollutant widely discharged as a component of hydrocarbon fuels, but its degradation in cold regions is a great challenge due to the harsh environmental conditions. To date, there is little information available concerning the biodegradation of phenol by indigenous Antarctic bacteria. This study addresses the isolation of three phenol-degrading bacterial strains from King George Island, Antarctica. Based on preliminary screening, three isolates (AQ5-05, AQ5-06 and AQ5-07) capable of completely degrading 0.5 g/L phenol within 120 h at 10 °C were selected for detailed study. Two were identified as Arthrobacter spp., and one Rhodococcus sp., based on 16S rRNA sequences. All strains were non-motile, Gram positive, oxidase negative and catalase positive. A study on the effects of parameters including temperature, pH, salinity and nitrogen source was conducted to optimise the conditions for phenol degradation. This revealed that the three isolates were psychrotolerant with the optimum temperature for phenol degradation between 10 and 15 °C. This study suggests the potential use of cold-adapted bacteria in the bioremediation of phenol over a wide range of low temperatures. © 2017, Springer-Verlag GmbH Germany, part of Springer Nature