Physicochemical properties of various alginate-based raft-forming antacid products: a comparative study

Background: Alginate-based, raft-forming antacid products with reflux suppressant activity are complex formulations expected to achieve effective raft formation and cause elimination or displacement of the acid pocket, which is typically manifested in gastroesophageal reflux disease (GERD).Methods: In the present study, six alginate-based raft-forming products commercially available in the Indian market were compared in terms of their acid neutralization properties, strength, resilience and structural and thermal properties of their rafts. Percent alginate content was also determined.Results: Rafts of products containing calcium-based antacids formed voluminous, porous and floating rafts within seconds of addition to the simulated gastric fluid (SGF) compared with the products that contained aluminium and magnesium-based antacids. Marked differences were not evident in the ANC (acid neutralization capacity) values of the various products. No correlation was observed between ANC and raft-forming capacity or duration of neutralization. Raft structures affected their neutralization profiles. Rafts of porous and absorbent nature could retain their ANC probably due to release of trapped antacids. Further, raft strengths of only two products were above the British Pharmacopoeia specification of not less than 7.5 g. Sodium alginate content was within specifications (85-115%) for three of the six products.Conclusions: Raft-forming formulations with higher alginate content and calcium-based antacids have better physicochemical properties such as ANC, neutralization profiles, raft strength and raft resilience than those with lower alginate content or those containing aluminium or magnesium-based antacids.

Vibration characteristics analysis of composite floating rafts for marine structure based on modal superposition theory

Composite materials have become a research hotspot in the field of vibration and noise reduction for their high strength, high damping, and other outstanding mechanical properties in recent years. In this paper, the effect of laminated materials on the dynamic performance of floating rafts is investigated based on modal superposition theory using the finite element method. The detailed derivation of the modal superposition theory was made, and taking T700 fiber-reinforced composite material as an example the damping effect of the floating raft structure in three cases was discussed: whether the composite material is laid or not, different layup angles, and different layup positions. The research shows that laying composite materials can improve damping effect of the floating raft and the changes in both the laying angle and the laying position will affect its dynamic performance. Moreover, the damping performance of the structure is inversely correlated with its stiffness within a certain range.

Korelasi Pertumbuhan Dan Kandungan Karaginan Kappaphycus alvarezii Dan Eucheuma Spinosum Dengan Jarak Penempatan Rakit Apung Yang Berbeda Di Desa Grujugan Kecamatan Gapura Kabupaten Sumenep [Correlation Of Growth And Carragenan Content Of Kappaphycus alvarezii And Eucheuma Spinosum By Different Distance Placement Of Floating Rafts At The Grujugan Village, Sub-District Gapura, Residence Of Sumenep]

The selection of right location is an important succeed factor of the seaweed cultivation to make seaweed a good growth. Seaweed Kappaphycus alvarezii and Eucheuma spinosum contain carrageenan which has been widely used in several industries. The aim of the research is to determine the correlation of growth and carrageenan content K. alvarezii and E. spinosum by different distance placement of floating rafts. Research method using experimental method and experimental design using randomized block design, followed by Duncan's test or Mann Whitney U test and furthermore linear correlation to determine the correlation between growth and carrageenan content. The treatment using different cultivation locations. On K. alvarezii with a distance of 100 m from the beach (RK1), a distance of 400 m from the beach (RK2), and a distance of 700 m from the beach (RK3). E. spinosum at a distance of 100 m from the beach (RE1), a distance of 400 m from the beach (RE2), and the distance of 700 m from the beach (RE3). Each treatment was repeated 9 times. The main parameters observed in this study is the growth rate of once every 10 days, and the content of carrageenan obtained from the extraction of the final harvest. Supporting water quality parameters include: temperature, water transparency, current velocity, substance nutrients (nitrate and phosphate), salinity, and pH. The results showed seaweed K. alvarezii and E. spinosum cultivated at a distance at 400 m from beach has the highest growth rate and yield best carrageenan content. From the results of the calculation of growth and carrageenan content K. alvarezii and E. spinosum with distance floating rafts of different placements had a very strong correlation

Floating rafts as breeding habitats for the Common tern, Sterna hirundo. Colonization patterns, abundance and reproductive success in Venice Lagoon

The Venice lagoon hosts the 15% of the entire Italian breeding population of Common terns, Sterna hirundo, highlighting the great value of the area for this species. However, in the last 25 years, a substantial decline of Common terns has been detected in the Lagoon, which culminated in 2008. The main causes of this negative trend were the loss of salt marsh habitats, where terns typically breed in the Venice lagoon. This was due to the increase in the mean sea level and the greater frequency of high tides during the reproductive period with consequent flooding of their breeding sites; competition with yellowlegged gulls (Larus michahellis), predation and human disturbance. As a preliminary experimental approach to counter the depletion of the species and favour its recovery, we performed a habitat loss compensation project by setting up four floating rafts (3x2m), covered by two different types of substrate (sandy and vegetal substrate). This was to function as an artificial nesting site safe from flooding, positioned in a protected internal wetland area of the Venice lagoon, Valle Averto (Sourthern Lagoon). We studied the colonization patterns of the rafts and the reproductive success of Common tern breeding pairs during the 2014 and 2015 breeding seasons. We also investigated those environmental and structural variables that could favour the use of the rafts and the nesting success of the species. In both years, the rafts were successfully colonized and used by terns for nesting. Our results also indicated higher temperature, lower rainfall and greater distance from the shore as the main habitat factors favouring the occurrence and the reproductive success of the breeding pairs, while a windrow of dead plants was indicated as the preferred substrate for covering rafts in order to make them more attractive. The results provided some suggestions for successful restoration plans to be developed in similar lagoon areas.

By-catch in no-fed aquaculture: exploiting mussel seed persistently and extensively disturbs the accompanying assemblage

Although aquaculture sometimes lessens the negative effects of fishing by lowering the need to capture wild animals and plants, some aquaculture practices still require the exploitation of wild populations. A largely overlooked case is the use of wild populations to provide seed to sea farms. Mussel farming in Northwest Spain involve the capture of thousands of tons of young mussels (0.5–2 cm long) from the nearby rocky intertidal every year to supply floating rafts. Despite its volume, the impact of this activity on other sessile organisms remains unassessed. To fill this gap in our knowledge, we monthly monitored the sessile intertidal assemblage of five protected and six exploited sites during the closed season in 2016 following a nested sampling plan. Like the by-catch typical of other fisheries, harvesting young mussels for aquaculture was detrimental to the abundance and diversity of the associated sessile assemblage not directly targeted by this activity. Coverage and richness were also significantly lowered by the exploitation of mussel seed, and the community structure of protected and exploited sites was significantly different. These differences continued until the next open season, suggesting that the closed season was too short for the recovery of the associated non-target sessile assemblage. Given the size of the local mussel industry, the incomplete recovery along the closed season implies that mussel aquaculture must be putting a sustained pressure on a sizeable portion of the rocky intertidal of Northwest Spain.

Effectiveness of domestic wastewater treatment using floating rafts a promising phyto-remedial approach: A review

Treatment of wastewater will lead to the problems again, if we will not use new more efficient alternative technologies/methods to avoid drawback of old technologies. Loss of water can be reduced through application of easy, inexpensive and eco-friendly technologies for wastewater treatment. Using Floating rafts to purify polluted wastewater is a process/method of ecological restoration at in-situ, as well as a complicated physical (attachment of pollutants to the root surface), chemical (degradation of metals into less toxic form) and biological process (microbial processes). Its core is utilizing aquatic plants such as Canna and Water lily and root attached microbes such as bac-teria, fungi and algae to absorb pollutants such as nitrogen and phosphorus, degrade organic matter and accumulates heavy metals in their biomass. Phytoremediation of polluted wastewater using the Floating rafts technique is an Eco-friendly method of wastewater treatment, which is economically effective to construct, requires little maintenance and increase the biodiversity as different types of plants are used. Floating rafts technique has been applied to some water pollution control projects at domestic and abroad. However, there are some factors such as plants, temperature, seasons, hydraulic retention time, coverage and initial concentration of pollutants etc. influenced to the pollutants removal efficiency of Floating rafts. In the future, the development orientation has been subjected to plant and its combinations, the transformation of Floating rafts structure and the utilization of aquatic plants, and probed the technology of Floating rafts building and management, to implement the win-win of landscape benefit and ecological function.

Research on the aerial mini SAR development and experiment on marine oil spill monitoring

Mini SAR was developed for the oil spill monitoring, working on C band, VV polarization, with the weight of 24kg and finest resolution of 0.5m, and could be aboard on manned and unmanned aerial vehicles. The mini SAR made the real time and continual imaging of large coverage available, and recorded the original signals for fine imaging further back to ground. The experiment was carried out in August and September of 2015 in Yantai and Weihai offshore waters, with the mini SAR on board the cruiser of State Oceanic Administration. And images of oil rigs, vessels, floating rafts and oil look likes were acquired with good quality. The images were interpreted and analyzed combing optical images, and the automatic detection of oil slick in mini SAR images was proposed. And it was indicated that the mini SAR provided high quality SAR images, supporting the oil slick detection and marine monitoring. Next the research on real time transmission of oil detection and early warning messages would be carried out to satisfy the time efficiency of oil spill monitoring.

SEARCHING FOR SOLUTIONS IN AQUACULTURE: AQUAPONICS

Aquaponic production combines intensive production with waste recycling and water conservation. Aquaponic join recirculating aquaculture with hydroponics to use nutrient waste from aquaculture as an input to plant growth. Traditional aquaculture systems treat or dispose nutrient-rich wastewater. In aquaponics, the waste products from the fish are converted by a bio-fi lter into soluble nutrients which are absorbed by the plants, and allow “clean” water to be returned back to the fish. Thus, it produces valuable fish protein with a minimal pollution of fresh water resources, while at the same time producing horticultural crops. Fish in aquaponic production systems can be raised in ponds, tanks, or other containers. Plants are grown separately in hydroponic tanks, submerged in water but suspended in gravel, sand, perlite, or porous plastic films, as well as on floating rafts. Systems vary greatly in design and construction, but most perform the following key functions: finfish and plant production, removal of suspended solids, and bacterial nitrification. This review discusses applications, effects and perspective of aquaponics.