Search results for: marine

Authors: Ricardo Paiva, Rui Soares, Felix Harnau, Bruno Fragoso

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Nickel-based alloys are materials well suited for service in extreme environments subjected to pressure and heat. Some industrial applications for Nickel-based alloys are aerospace and jet engines, oil and gas extraction, pollution control and waste processing, automotive and marine industry. It is generally recognized that grain refinement is an effective methodology to improve the quality of casted parts. Conventional grain refinement techniques involve the addition of inoculation substances, the control of solidification conditions, or thermomechanical treatment with recrystallization. However, such methods often lead to non-uniform grain size distribution and the formation of hard phases, which are detrimental to both wear performance and biocompatibility. Stirring of the melt by electromagnetic fields has been widely used in continuous castings with success for grain refinement, solute redistribution, and surface quality improvement. Despite the advantages, much attention has not been paid yet to the use of this approach on functional castings such as investment casting. Furthermore, the effect of electromagnetic stirring (EMS) fields on Nickel-based alloys is not known. In line with the gaps/needs of the state-of-art, the present research work targets to promote new advances in controlling grain size and morphology of investment cast Nickel based alloys. For such a purpose, a set of experimental tests was conducted. A high-frequency induction furnace with vacuum and controlled atmosphere was used to cast the Inconel 718 alloy in ceramic shells. A coil surrounded the casting chamber in order to induce electromagnetic stirring during solidification. Aiming to assess the effect of the electromagnetic stirring on Ni alloys, the samples were subjected to microstructural analysis and mechanical tests. The results show that electromagnetic stirring can be an effective methodology to modify the grain size and mechanical properties of investment-cast parts.

Keywords: investment casting, grain refinement, electromagnetic stirring, nickel alloys

Procedia PDF Downloads 132

Authors: Yasir M. Alyazichi, Brian G. Jones, Errol McLean, Hamd N. Altalyan, Ali K. M. Al-Nasrawi

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The main purpose of this study is to assess the sediment quality and potential ecological risk in marine sediments in Gymea Bay located in south Sydney, Australia. A total of 32 surface sediment samples were collected from the bay. Current track trajectories and velocities have also been measured in the bay. The resultant trace elements were compared with the adverse biological effect values Effect Range Low (ERL) and Effect Range Median (ERM) classifications. The results indicate that the average values of chromium, arsenic, copper, zinc, and lead in surface sediments all reveal low pollution levels and are below ERL and ERM values. The highest concentrations of trace elements were found close to discharge points and in the inner bay, and were linked with high percentages of clay minerals, pyrite and organic matter, which can play a significant role in trapping and accumulating these elements. The lowest concentrations of trace elements were found to be on the shoreline of the bay, which contained high percentages of sand fractions. It is postulated that the fine particles and trace elements are disturbed by currents and tides, then transported and deposited in deeper areas. The current track velocities recorded in Gymea Bay had the capability to transport fine particles and trace element pollution within the bay. As a result, hydrodynamic measurements were able to provide useful information and to help explain the distribution of sedimentary particles and geochemical properties. This may lead to knowledge transfer to other bay systems, including those in remote areas. These activities can be conducted at a low cost, and are therefore also transferrable to developing countries. The advent of portable instruments to measure trace elements in the field has also contributed to the development of these lower cost and easily applied methodologies available for use in remote locations and low-cost economies.

Keywords: current track velocities, gymea bay, surface sediments, trace elements

Procedia PDF Downloads 245

Authors: Despoina Andrioti Bygvraa, Ida-Maja Hassellöv, George Charalambous

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Exhaust gas cleaning systems, also known as scrubbers, are today widely used to allow for the use of High Sulphur Heavy Fuel Oil and still comply with the regulations limiting sulphur content in marine fuels. There are extensive concerns about environmental consequences, especially in the Baltic Sea, from the wide-scale use of scrubbers, as the wash water is acidic (ca pH 3) and contains high concentrations of toxic, carcinogenic, and mutagenic substances. The aim of this feasibility study is to investigate the potential adverse effects on seafarers’ health with the ultimate goal of raising awareness of chemical-related health and safety issues in the shipping environment. The project got funding from the Swedish Foundation. The team will extend previously compiled data on scrubber wash water concentrations of hazardous substances and pH to include the use of strong base in closed-loop scrubbers, and scoping assessment on handling and disposing practices. Based on the findings (a), a systematic review of risk assessment will follow to show the risk of exposures, the establishment of the hazardous levels for human health as well as the respective prevention practices. In addition, the researchers will perform (b) a systematic review to identify facilitators and barriers of the crew on compliance with the safe handling of chemicals. The study will run for 12 months, delivering (a) a risk assessment inventory with risk exposures and (b) a course description of safe handling practices. This feasibility study could provide valuable knowledge on how pollutants found in scrubbers should be considered from a human health perspective to facilitate evidence-based informed decisions in future technology- and policy development to make shipping a safer, healthier, and more attractive workplace.

Keywords: health and safety, seafarers, scrubbers, chemicals, risk exposures

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Authors: Flóra Pomázi, Sándor Baranya, Zoltán Szalai

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A harmonized monitoring of the suspended sediment transport along such a large river as the world’s most international river, the Danube River, is a rather challenging task. The traditional monitoring method in Hungary is obsolete but using indirect measurement devices and techniques like optical backscatter sensors (OBS), laser diffraction or acoustic backscatter sensors (ABS) could provide a fast and efficient alternative option of direct methods. However, these methods are strongly sensitive to the particle characteristics (i.e. particle shape, particle size and mineral composition). The current method does not provide sufficient information about particle size distribution, mineral analysis is rarely done, and the shape of the suspended sediment particles have not been examined yet. The aims of the study are (1) to determine the particle characterisation of suspended sediment in the Danube River using advanced particle characterisation methods as laser diffraction and automated imaging, and (2) to perform a sensitivity analysis of the indirect methods in order to determine the impact of suspended particle characteristics. The particle size distribution is determined by laser diffraction. The particle shape and mineral composition analysis is done by the Morphologi G3ID image analyser. The investigated indirect measurement devices are the LISST-Portable|XR, the LISST-ABS (Sequoia Inc.) and the Rio Grande 1200 kHz ADCP (Teledyne Marine). The major findings of this study are (1) the statistical shape of the suspended sediment particle - this is the first research in this context, (2) the actualised particle size distribution – that can be compared to historical information, so that the morphological changes can be tracked, (3) the actual mineral composition of the suspended sediment in the Danube River, and (4) the reliability of the tested indirect methods has been increased – based on the results of the sensitivity analysis and the previous findings.

Keywords: advanced particle characterisation, automated imaging, indirect methods, laser diffraction, mineral composition, suspended sediment

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Authors: H. M. Zakir Hossain

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Cenozoic mudstone samples, obtained from drilled cored and outcrop in northeastern Bengal Basin of Bangladesh were organic geochemically analyzed to identify vertical variations of organic facies, thermal maturity, hydrocarbon potential and depositional environments. Total organic carbon (TOC) content ranges from 0.11 to 1.56 wt% with an average of 0.43 wt%, indicating a good source rock potential. Total sulphur content is variable with values ranging from ~0.001 to 1.75 wt% with an average of 0.065 wt%. Rock-Eval S1 and S2 yields range from 0.03 to 0.14 mg HC/g rock and 0.01 to 0.66 mg HC/g rock, respectively. The hydrogen index values range from 2.71 to 56.09 mg HC/g TOC. These results revealed that the samples are dominated by type III kerogene. Tmax values of 426 to 453 °C and vitrinite reflectance of 0.51 to 0.66% indicate the organic matter is immature to mature. Saturated hydrocarbon ratios such as pristane, phytane, steranes, and hopanes, indicate mostly terrigenous organic matter with small influence of marine organic matter. Organic matter in the succession was accumulated in three different environmental conditions based on the integration of biomarker proxies. First phase (late Eocene to early Miocene): Deposition occurred entirely in seawater-dominated oxic conditions, with high inputs of land plants organic matter including angiosperms. Second phase (middle to late Miocene): Deposition occurred in freshwater-dominated anoxic conditions, with phytoplanktonic organic matter and a small influence of land plants. Third phase (late Miocene to Pleistocene): Deposition occurred in oxygen-poor freshwater conditions, with abundant input of planktonic organic matter and high influx of angiosperms. The lower part (middle Eocene to early Miocene) of the succession with moderate TOC contents and primarily terrestrial organic matter could have generated some condensates and oils in and around the study area.

Keywords: Bangladesh, geochemistry, hydrocarbon potential, mudstone

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Authors: Stephanie Hernández-Carreón, Judith Virginia Ríos-Arana

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Microplastics (MPs) are plastic particles smaller than 5 mm that has been detected in soil, air, organisms, and mostly water around the world. Most studies have focused on MPs detection in marine waters, and less so in freshwater, such is the case of Mexico, where studies about MPs in freshwaters are limited. One of the most important rivers in the country is The Rio Grande/Río Bravo, a natural border between Mexico and the United States. Its waters serve different purposes, such as fishing, habitat to endemic species, electricity generation, agriculture, and drinking water sources, among others. Despite its importance, the river’s waters have not been analyzed to determine the presence of MPs; therefore, the purpose of this research is to determine if the Rio Bravo/Rio Grande is polluted with microplastics. For doing so, three sites (Borderland, Casa de Adobe, and Guadalupe) along the El Paso-Juárez metroplex have been sampled: 30 L of water were filtered through a plankton net (64 µm) in each site and sediments-composed samples were collected. Water samples and sediments were 1) digested with a hydrogen peroxide solution (30%), 2) resuspended in a calcium chloride solution (1.5 g/cm3) to separate MPs, and 3) filtered through a 0.45 µm nitrocellulose membrane. Processed water samples were dyed with Nile Red (1 mg/ml ethanol) and analyzed by fluorescence microscopy. Two water samples have been analyzed until January 2023: Casa de Adobe and Borderland finding a concentration of 5.67 particles/L and 5.93 particles/L, respectively. Three types of particles were observed: fibers, fragments, and films, fibers being the most abundant. These data, as well as the data obtained from the rest of the samples, will be analyzed by an ANOVA (α=0.05). The concentrations and types of particles found in the Río Bravo correspond with other studies on rivers associated with urban environments and agricultural activities in China, where a range of 3.67—10.7 particles/L was reported in the Wei River. Even though we are in the early stages of the study, and three new sites will be sampled and analyzed in 2023 to provide more data about this issue in the river, this presents the first evidence of microplastic pollution in the Rio Grande.

Keywords: microplastics, fresh water, Rio Bravo, fluorescence microscopy

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Authors: Brian M. Mehling, Louis Quartararo, Marine Manvelyan, Paul Wang, Dong-Cheng Wu

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Numerous investigations suggest that Mesenchymal Stem Cells (MSCs) in general represent a valuable tool for therapy of symptoms related to chronic inflammatory diseases. Blue Horizon Stem Cell Therapy Program is a leading provider of adult and children’s stem cell therapies. Uniquely we have safely and efficiently treated more than 600 patients with documenting each procedure. The purpose of our study is primarily to monitor the immune response in order to validate the safety of intravenous infusion of human umbilical cord blood derived MSCs (UC-MSCs), and secondly, to evaluate effects on biomarkers associated with chronic inflammation. Nine patients were treated for conditions associated with chronic inflammation and for the purpose of anti-aging. They have been given one intravenous infusion of UC-MSCs. Our study of blood test markers of 9 patients with chronic inflammation before and within three months after MSCs treatment demonstrates that there is no significant changes and MSCs treatment was safe for the patients. Analysis of different indicators of chronic inflammation and aging included in initial, 24-hours, two weeks and three months protocols showed that stem cell treatment was safe for the patients; there were no adverse reactions. Moreover data from follow up protocols demonstrates significant improvement in energy level, hair, nails growth and skin conditions. Intravenously administered UC-MSCs were safe and effective in the improvement of symptoms related to chronic inflammation. Further close monitoring and inclusion of more patients are necessary to fully characterize the advantages of UC-MSCs application in treatment of symptoms related to chronic inflammation.

Keywords: chronic inflammatory diseases, intravenous infusion, stem cell therapy, umbilical cord blood derived mesenchymal stem cells (UC-MSCs)

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Authors: Werede Girmay Tesfasilasiea

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Three stratigraphic sections of the Antalo Limestone successions in Mekelle Outlier, northern Ethiopia (at Hagere-Selam, Messobo, and Wukro sections) have been investigated to distinguish their microfacies features, reservoir characterization, and their equivalent depositional environments. The Antalo Limestone successions were deposited in the Mekelle Outlier during the Upper Jurassic period as a result of flooding of the area by the Tethys Ocean toward the southeast direction. This study is based on field description and petrographic analysis to determine the depositional environment, age, and reservoir characteristics of the carbonate units. According to petrographical studies of 100 thin sections and field investigation, 14 microfacies types are recognized. These are grouped into 4 microfacies association of a tidal flat (MFT1-2), lagoons (MFL1-2), shoal (MFS1-4), and open marine environment (MFO1-6). Hence, the Antalo limestone successions are deposited in shallow carbonate ramps with a wide lateral and vertical distribution of facies. The carbonate units in the studied sections are affected by bioturbation, micritization, cementation, dolomitization, dissolution, silicification, and compaction type of early diagenetic alteration. Dissolution and dolomitization affected the type of rock, showing good reservoir quality, while cementation and compaction affected the type of rock, resulting in poor reservoir quality in the Antalo Limestone successions of the Mekelle outlier. Based on the abundant distribution of the Alveosepta jaccardi (Schrodt), Pseudocyclammina lituus (Yokoyama), Kurnubia palestiniensis (Henson), and Somalirhynchia africana in the studied sections the Antalo Limestone successions assigned to the Late Oxfordian-Kimmeridgian age.

Keywords: Antelo limestone successions, depositional environment, Mekelle outlier, microfacies analysis, diagenesis, reservoir quality

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Authors: P. Mandree, S. O. Ramchuran, F. O'Brien, L. Sethunya, S. Khumalo

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South Africa is identified as one of the five emerging waste management markets, globally. The waste sector in South Africa influences the areas of energy, water and food at an economic and social level. Recently, South African industries have focused on waste valorization and diversification of the current product offerings in an attempt to reduce industrial waste, target a zero waste-to-landfill initiative and recover energy. South Africa has a number of waste streams including industrial and agricultural biomass, municipal waste and marine waste. Large volumes of agricultural and forestry residues, in particular, are generated which provides significant opportunity for production of bio-based fuels and chemicals. This could directly impact development of a rural economy. One of the largest agricultural industries is the sugar industry, which contributes significantly to the country’s economy and job creation. However, the sugar industry is facing challenges due to fluctuations in sugar prices, increasing competition with low-cost global sugar producers, increasing energy and agricultural input costs, lower consumption and aging facilities. This study is aimed at technology development for the production of various bio-based chemicals using feedstock from the sugar refining process. Various indigenous bacteria and yeast species were assessed for the potential to produce platform chemicals in flask studies and at 30 L fermentation scale. Quantitative analysis of targeted bio-based chemicals was performed using either gas chromatography or high pressure liquid chromatography to assess production yields and techno-economics in order to compare performance to current commercial benchmark processes. The study also creates a decision platform for the research direction that is required for strain development using Industrial Synthetic Biology.

Keywords: bio-based chemicals, biorefinery, industrial synthetic biology, waste valorization

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Authors: Jose Melena, Rosa Santander, Tanya Gonzalez, Richard Duque, Juan Illanes

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Ecuador is one of the countries with the greatest aquatic biodiversity worldwide. In particular, there are at least a dozen native marine species with great aquaculture potential locally. This research concerns one of those species. It has proposed to implement experimental protocols in order to induce spawning and to generate the early larval development of the penshell Atrina maura under controlled conditions. Bioassays were carried out with one adult batch (n= 26) with an average valvar length of 307,6 ± 9,4 mm, which were collected in the Puerto El Morro Mangrove (2° 42' 33'' S, 80° 14' 28'' W), Guayas Province. During a short acclimation stage, five adults of penshell A. maura were sacrificed in order to determine their sexual maturity degree and to estimate their sex ratio. Dissection showed that three were ripe females (60%) and two were ripe males (40%). Later, three groups (n= 7 by each) were tested with two treatments in order to induce the broodstock spawning: thermal stress, osmotic shock, and one control. Spawning induction was achieved by the immersion in water to 0 g L⁻¹ per 1 h and immersion in sea water to 34 g L⁻¹ per 1 h. After the delivery of gametes, it was achieved 1,35 × 10⁶ viable zygotes. As results, fertilized eggs had 60 µm diameter; while first and second cell divisions were observed to 1 h post-fertilization, with individual average length of 65 ± 4 µm and polar body. Latter cell divisions, including gastrula stage, appeared at 9 h post-fertilization, with individual average length of 71 ± 4 µm; and trochophore stage at 16 h post-fertilization with individual average length of 75 ± 5 µm. In addition, veliger stage was registered at 20 h post-fertilization with individual average length of 81 ± 5 µm. Umboned larvae appeared at day 8 post-fertilization, with individual average length of 145 ± 6 µm. These pioneering results in Ecuador can strengthen the local conservation process of the overexploited A. maura and to encourage its production for commercial purposes.

Keywords: Atrina maura, Ecuador, larval development, spawning induction

Procedia PDF Downloads 163

Authors: Aimen Saleh

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The Silurian Lower Acacus sandstone is one of the main reservoirs in North West Libya. Our aim in this study is to grasp a robust understanding of the hydrocarbon potential and distribution in the area. To date, the depositional environment of the Lower Acacus reservoir still open to discussion and contradiction. Henceforth, building three dimensional (3D) property modelling is one way to support the analysis and description of the reservoir, its properties and characterizations, so this will be of great value in this project. The 3D model integrates different data set, these incorporates well logs data, petrophysical reservoir properties and seismic data as well. The finalized depositional environment model of the Lower Acacus concludes that the area is located in a deltaic transitional depositional setting, which ranges from a wave dominated delta into tide dominated delta type. This interpretation carried out through a series of steps of model generation, core description and Formation Microresistivity Image tool (FMI) interpretation. After the analysis of the core data, the Lower Acacus layers shows a strong effect of tidal energy. Whereas these traces found imprinted in different types of sedimentary structures, for examples; presence of some crossbedding, such as herringbones structures, wavy and flaser cross beddings. In spite of recognition of some minor marine transgression events in the area, on the contrary, the coarsening upward cycles of sand and shale layers in the Lower Acacus demonstrate presence of a major regressive phase of the sea level. However, consequently, we produced a final package of this model in a complemented set of facies distribution, porosity and oil presence. And also it shows the record of the petroleum system, and the procedure of Hydrocarbon migration and accumulation. Finally, this model suggests that the area can be outlined into three main segments of hydrocarbon potential, which can be a textbook guide for future exploration and production strategies in the area.

Keywords: Acacus, Ghadames , Libya, Silurian

Procedia PDF Downloads 143

Authors: Kuan Yin Hsiao, Shyh Ming Kuo, Yi Jhen Wu, Chin Wen Chuang, Chuen-Fu Lin, Wei-qing Yang, Han Hsiang Huang

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Anti-tumor effects of natural products, like compounds from marine sponges and soft corals, have been investigated for decades. Polymeric nanoparticles prepared from biodegradable and biocompatible molecules, such as Hyaluronan (HA), Chitosan (CHI) and gelatin have been widely studied. Encapsulation of anti-cancer therapies by the biopolymeric nanoparticles in drug delivery system is potentially capable of improving the therapeutic effects and attenuating their toxicity. In the current study, the anti-bladder cancer effects of heteronemin extracted from the sponge Hippospongia sp. with or without HA and CHI nanoparticle encapsulation were assessed and evaluated in vitro. Results showed that IC50 (half maximal inhibitory concentration) of heteronemin toward T24 human bladder cancer cell viability is approximately 0.18 µg/mL. Both plain and HA nanoparticles-encapsulated heteronemin at 0.2 and 0.4 µg/mL significantly reduced T24 cell viability (P<0.001) while HA nanoparticles-encapsulated heteronemin showed weaker viability-inhibitory effects on L929 fibroblasts compared with plain heteronemin at the identical concentrations. HA and CHI nanoparticles-encapsulated heteronemin exhibited significantly stronger inhibitory effects against migration of T24 human bladder cancer cell than those exerted by plain heteronemin at the same concentrations (P<0.001). The flow cytometric results showed that 0.2 µg/mL HA and CHI nanoparticles-encapsulated heteronemin induced higher early apoptosis rate than that induced by plain heteronemin at the same concentration. These results show that HA and CHI nanoparticle encapsulation is able to elevate anti-migratory and apoptosis-inducing effects exerted by heteronemin against bladder cancer cells in vitro. The in vivo anti-bladder cancer effects of the compound with or without HA/CHI nanoparticle encapsulation will be further investigated and examined using murine tumor models. The data obtained from this study will extensively evaluate of the anti-bladder cancer effects of heteronemin as well as HA/CHI-encapsulated heteronemin and pave a way to develop potential bladder cancer treatment.

Keywords: heteronemin, nanoparticles, hyaluronan, chitosan, bladder cancer

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Authors: Parisa Afshin, Terje Grønning

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Norway, similar to many other countries, has set the focus of its policies in creating new strong and highly innovative sectors in recent years, as the oil and gas sector profitability is declining. Biotechnology sector in Norway has a great potential, especially in marine-biotech and cancer medicine. However, Norway being a periphery faces especial challenges in the path of creating internationally well-known biotech sector and an international knowledge hub. The aim of this article is to analyze the progress of the Norwegian biotechnology industry, its pathway to build up an innovation network and conduct collaborative innovation based on its initial conditions and its own advantage and disadvantages. The findings have important implications not only for politicians and academic in understanding the infrastructure of biotechnology sector in the country, but it has important lessons for other periphery countries or regions aiming in creating strong biotechnology sector and catching up with the strong internationally-recognized regions. Data and methodology: To achieve the main goal of this study, information has been collected via secondary resources such as web pages and annual reports published by the officials and mass media along with interviews were used. The data were collected with the goal to shed light on a brief history and current status of Norway biotechnology sector, as well as geographic distribution of biotech industry, followed by the role of academic and industry collaboration and public policies in Norway biotech. As knowledge is the key input in innovation, knowledge perspective of the system such as knowledge flow in the sector regarding the national and regional innovation system has been studied. Primary results: The internationalization has been an important element in development of periphery regions' innovativeness enabling them to overcome their weakness while putting more weight on the importance of regional policies. Following such findings, suggestions on policy decision and international collaboration, regarding national and regional system of innovation, has been offered as means of promoting strong innovative sector.

Keywords: biotechnology sector, knowledge-based industry, national innovation system, regional innovation system

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Authors: Trianasari, Gede Adi Yuniarta

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The tourism industry has been widely recognized as one of the world’s largest industries and is expected to have continuous growth. While it has positive impacts especially on the job markets and economic aspect, this industry also brings serious environmental impacts that may not be neglected. As such, the tourism industry is faced with increasing demands and challenges to deal with the environmental issues. Corporate Social Responsibility (CSR) is a way to show the firms’ concern on the societal and environmental aspects. In line with the increasing pressure on such responsibilities, a growing number of firms have involved in CSR activities. In Bali, the majority of both chained and locally owned hotels have shown their efforts on CSR practices. However, little is known about what and how they perform or implement such program especially within the environmental aspect. The importance of understanding what they focus on lays in the identification of areas that have received sufficient treatment and those that require more attention. Furthermore, also, it is especially essential considering that Bali is one of the worldly known destinations that have been facing numerous crucial issues on environment that may threaten the sustainability of the island and its people. This paper reports on the results of a study exploring the practices of CSR in hotels in Bali. Data were collected from 49 hotel managers and human resource managers in Bali across four major tourist areas, using semi structured interview method. The analysis was conducted qualitatively. The results showed that all hotels under study have implemented CSR activities in which environment was found to be the second key aspect, following the activities directly related to community aspect. Moreover, there were five major types of environmental action identified: beach cleaning, replantation, marine conservation, turtle conservation, mangrove, and garbage management. These findings suggest that hotels in Bali under study have shown their concern on the environment, however, less attention was given on attempt to reduce the environmental impacts of their operations. Mapping the types of environmental related CSR activities enhances the knowledge of and gives lights into the CSR literature especially from the perspective of Eastern practice.

Keywords: CSR, exploratory study, sustainable tourism, tourist object

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Authors: Alfathony Krisnabudhi, Syahli Reza Ananda, M. Edo Marshal, M. Maaruf Mukti

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This study investigates the kinematics and basin development of pull-apart basin Sunda Strait based on palinspastic reconstructions of new acquired seismic reflection data to unravel hydrocarbon exploration opportunity in frontier area, fore-arc basin western Indonesia. We use more than 780 km seismic reflection data that cover whole basin. Structural patterns in Sunda Strait are dominated by northwest-southeast trending planar and listric-normal faults which appear to be graben and half-graben system. The main depocentre of this basin is East Semangko graben and West Semangko graben that are formed by overstepping of Sumatra Fault Zone and Ujungkulon Fault Zone. In father east, another depocentre is recognized as the Krakatau graben. The kinematic evolution started in Middle Miocene, characterized by the initiation of basement faulting with 0% to 7.00% extension. Deposition stratigraphic unit 1 and unit 2 started at 7.00% to 10.00% extension in Late Miocene and recognized as pre-transtensional deposit. The Plio-Pleistocene unit 3 and 4 were deposited as syn-transtensional deposit with 10.00% to 17.00% extension contemporaneously with the initiation of uplift NW-SE trending ridges due to the evolution of cross-basin fault in central basin and the development of en-echelon basin margin in a transtensional system. The control of sedimentation rate and basin subsidence cause the Neogene sediment to be very thick. We suggest that both controls allow thermal and pressure to generate hydrocarbon habitats in the pre-transtensional deposits. It is reinforced by stable kinematic evolution and interpretation of the deposition environment of pre-transtensional deposits that are deposited in the marine environment.

Keywords: kinematics, palinspastic, Sunda Strait, hydrocarbon exploration, fore-arc basin

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Authors: Charmi Chande, Ravindra Phadke

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Microfluidics devices are fabricated by using multiple fabrication methods. Photolithography is one of the common methods wherein SU8 is widely used for making master which in turn is used for making working chip by the process of soft lithography. The high-aspect ratio features of SU-8 makes it suitable to be used as micro moulds for injection moulding, hot embossing, and moulds to form polydimethylsiloxane (PDMS) structures for bioMEMS (Microelectromechanical systems) applications. But due to high cost, difficulty in procuring and need for clean room, restricts the use of this polymer especially in developing countries and small research labs. ‘Bisphenol –A’ based polymers in mixture with curing agent are used in various industries like Paints and coatings, Adhesives, Electrical systems and electronics, Industrial tooling and composites. We present the novel use of ‘Bisphenol – A’ based polymer in fabricating micro channels for Lab On Chip(LOC) devices. The present paper describes the prototype for production of microfluidics chips using range of ‘Bisphenol-A’ based polymers viz. GY 250, ATUL B11, DER 331, DER 330 in mixture with cationic photo initiators. All the steps of chip production were carried out using an inexpensive approach that uses low cost chemicals and equipment. This even excludes the need of clean room. The produced chips using all above mentioned polymers were validated with respect to height and the chip giving least height was selected for further experimentation. The lowest height achieved was 7 micrometers by GY250. The cost of the master fabricated was $ 0.20 and working chip was $. 0.22. The best working chip was used for morphological identification and profiling of microorganisms from environmental samples like soil, marine water and salt water pan sites. The current chip can be adapted for various microbiological screening experiments like biochemical based microbial identification, studying uncultivable microorganisms at single cell/community level.

Keywords: bisphenol–A based epoxy, cationic photoinitiators, microfabrication, photolithography

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Authors: Haruka Ito, Toru Maruyama, Michihiro Ito, Chuya Shinzato, Hiroyuki Fujimura, Yoshikatsu Nakano, Shoichiro Suda, Sachiyo Aburatani, Haruko Takeyama

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Clarifying symbiotic relationships is one of the most important theme for understanding the marine eco-system. Coral reef has been regarded as an important environmental resource. Coral holobiont composed by coral, symbiotic microalgae zooxanthellae, and bacteria have complexed relationship. Zooxanthellae mainly supply organic matter to the host corals through their photosynthetic activity. The symbiotic relationship is indispensable for corals but may easily collapses due to the rise of seawater temperature. However, the molecular mechanism how seawater temperature influences their relationships still remain unclear. In this study, the transcriptomic analysis has applied to elucidate the coral-zooxanthellae relationships under high seawater temperature stress. To observe reactions of corals and zooxanthellae against the rise of seawater temperature, meta-gene expression in coral have been analyzed. The branches from six different colonies of a stony coral, Acropora tenuis, were sampled at nine times by 2016 at two locations, Ishikawabaru and South of Sesoko Island, Okinawa, Japan. The mRNAs extracted from the branches including zooxanthellae were sequenced by illumina HiSeq. Gene Set Enrichment Analysis (GSEA) based on hyper geometric distribution was performed. The seawater temperature at 2016 summer was unusually high, which was caused by El Niño event, and the number of zooxanthellae in coral was decreased in August. GSEA derived the several specific genes expressed in A. tenuis under heat stress conditions. The upregulated genes under heat stress highly related with infection immunity. The downregulated genes significantly contained cell cycle related genes. Thu, it is considered that heat stress cause disorder in cell metabolism of A. tenuis, resulting in serious influence to coral holobiont.

Keywords: coral, symbiosis, thermal stress response, transcriptome analysis

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Authors: Indunil Jayatilake, Warna Karunasena

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Fiber Reinforced Polymer (FRP) composites enjoy an array of applications ranging from aerospace, marine and military to automobile, recreational and civil industry due to their outstanding properties. A structural glass fiber reinforced polymer (GFRP) composite sandwich panel made from E-glass fiber skin and a modified phenolic core has been manufactured in Australia for civil engineering applications. One of the major mechanisms of damage in FRP composites is skin-core debonding. The presence of debonding is of great concern not only because it severely affects the strength but also it modifies the dynamic characteristics of the structure, including natural frequency and vibration modes. This paper deals with the investigation of the dynamic characteristics of a GFRP beam with single and multiple debonding by finite element based numerical simulations and analyses using the STRAND7 finite element (FE) software package. Three-dimensional computer models have been developed and numerical simulations were done to assess the dynamic behavior. The FE model developed has been validated with published experimental, analytical and numerical results for fully bonded as well as debonded beams. A comparative analysis is carried out based on a comprehensive parametric investigation. It is observed that the reduction in natural frequency is more affected by single debonding than the equally sized multiple debonding regions located symmetrically to the single debonding position. Thus it is revealed that a large single debonding area leads to more damage in terms of natural frequency reduction than isolated small debonding zones of equivalent area, appearing in the GFRP beam. Furthermore, the extents of natural frequency shifts seem mode-dependent and do not seem to have a monotonous trend of increasing with the mode numbers.

Keywords: debonding, dynamic response, finite element modelling, novel FRP beams

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Authors: Surya Prakash Gajagouni, Akram Alfantazi, Imad Barsoum

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Austenitic stainless steels are widely recognized for their exceptional corrosion resistance and mechanical properties, rendering them indispensable materials across various industries from construction to biomedical applications. However, in chloride and high temperature atmosphere it to further enhance their surface properties, anodization has emerged as a promising surface treatment technique. Anodization modifies the surface of stainless steels by creating a protective oxide layer, improving corrosion resistance and imparting additional functional characteristics. This paper explores the structural and corrosion characteristics of anodized austenitic stainless steels (AISI 304) using a two-step anodic technique. We utilized a perchloric acid-based electrolyte followed by an ammonium fluoride-based electrolyte. This sequential approach aimed to cultivate deeper and intricately self-ordered nanopore oxide arrays on a substrate made of 304 stainless steel. Electron Microscopic (SEM and TEM) images revealed nanoporous layered structures with increased length and crack development correlating with higher voltage and anodization time. Surface composition and chemical oxidation state of surface-treated SS were determined using X-ray photoelectron spectroscopy (XPS) techniques, revealing a surface layer rich in Ni and suppressed Cr, resulting in a thin film composed of Ni and Fe oxide compared to untreated SS. Electrochemical studies demonstrated enhanced corrosion resistance in a strong alkaline medium compared to untreated SS. Understanding the intricate relationship between the structural features of anodized stainless steels and their corrosion resistance is crucial for optimizing the performance of these materials in diverse applications. This study aims to contribute to the advancement of surface engineering strategies for enhancing the durability and functionality of austenitic stainless steels in aggressive environments.

Keywords: austenitic stainless steel, anodization, nanoporous oxides, marine corrosion

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Authors: Yong-Kian Lim, Khan Cheung, Xin Dang, Steven Roberts, Xiaotong Wang, Vengatesen Thiyagarajan

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Unprecedented rate of increased CO₂ level in the ocean and the subsequent changes in carbonate system including decreased pH, known as ocean acidification (OA), is predicted to disrupt not only the calcification process but also several other physiological and developmental processes in a variety of marine organisms, including edible oysters. Nonetheless, not all species are vulnerable to those OA threats, e.g., some species may be able to cope with OA stress using environmentally induced modifications on gene and protein expressions. For example, external environmental stressors, including OA, can influence the addition and removal of methyl groups through epigenetic modification (e.g., DNA methylation) process to turn gene expression “on or off” as part of a rapid adaptive mechanism to cope with OA. In this study, the above hypothesis was tested through testing the effect of OA, using decreased pH 7.4 as a proxy, on the DNA methylation pattern of an endemic and a commercially important estuary oyster species, Crassostrea hongkongensis, at the time of larval habitat selection and metamorphosis. Larval growth rate did not differ between control pH 8.1 and treatment pH 7.4. The metamorphosis rate of the pediveliger larvae was higher at pH 7.4 than those in control pH 8.1; however, over one-third of the larvae raised at pH 7.4 failed to attach to an optimal substrate as defined by biofilm presence. During larval development, a total of 130 genes were differentially methylated across the two treatments. The differential methylation in the larval genes may have partially accounted for the higher metamorphosis success rate under decreased pH 7.4 but with poor substratum selection ability. Differentially methylated loci were concentrated in the exon regions and appear to be associated with cytoskeletal and signal transduction, oxidative stress, metabolic processes, and larval metamorphosis, which implies the high potential of C. hongkongensis larvae to acclimate and adapt through non-genetic ways to OA threats within a single generation.

Keywords: adaptive plasticity, DNA methylation, larval metamorphosis, ocean acidification

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Authors: Zimu Li, Zheng Wan

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The Suez Canal plays an important role in global shipping networks and is one of the most frequently used waterways in the world. The 2021 canal obstruction by ship Ever Given in March 2021, however, completed blocked the Suez Canal for a week and caused significant disruption to world trade. Therefore, it is very important to quantitatively analyze the impact of the accident on the robustness of the global shipping network. However, the current research on maritime transportation networks is usually limited to local or small-scale networks in a certain region. Based on the complex network theory, this study establishes a global shipping complex network covering 2713 nodes and 137830 edges by using the real trajectory data of the global marine transport ship automatic identification system in 2018. At the same time, two attack modes, deliberate (Suez Canal Blocking) and random, are defined to calculate the changes in network node degree, eccentricity, clustering coefficient, network density, network isolated nodes, betweenness centrality, and closeness centrality under the two attack modes, and quantitatively analyze the actual impact of Suez Canal Blocking on the robustness of global shipping network. The results of the network robustness analysis show that Suez Canal blocking was more destructive to the shipping network than random attacks of the same scale. The network connectivity and accessibility decreased significantly, and the decline decreased with the distance between the port and the canal, showing the phenomenon of distance attenuation. This study further analyzes the impact of the blocking of the Suez Canal on Chinese ports and finds that the blocking of the Suez Canal significantly interferes withChina's shipping network and seriously affects China's normal trade activities. Finally, the impact of the global supply chain is analyzed, and it is found that blocking the canal will seriously damage the normal operation of the global supply chain.

Keywords: global shipping networks, ship AIS trajectory data, main channel, complex network, eigenvalue change

Procedia PDF Downloads 182

Authors: Waddah Abdullah, Saleh Al-Sarem

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Electrokinetic remediation was undoubtedly proven to be one of the most efficient techniques used to clean up soils contaminated with polar charged contaminants (such as heavy metals) and non-polar organic contaminants. It can be efficiently used to clean up low permeability mud, wastewater, electroplating wastes, sludge, and marine dredging. This study presented and discussed the results of electrokinetic remediation processes to clean up soils contaminated with nickel. Two types of electrokinetics cells were used: an open cell and an advanced cylindrical cell. Two types of soils were used for this investigation; the Azraq green clay which has very low permeability taken from the eastern part of Jordan (city of Azraq) and a sandy soil having, relatively, very high permeability. The clayey soil was spiked with 500 ppm of nickel, and the sandy soil was spiked with 1500 ppm of nickel. Fully saturated and partially saturated clayey soils were used for the clean-up process. Clayey soils were tested under a direct current of 80 mA and 50 mA to study the effect of the electrical current on the remediation process. Chelating agent (Na-EDTA), disodium ethylene diamine tetraacetatic acid, was used in both types of soils to enhance the electroremediation process. The effect of carbonates presence in the contaminated soils, also, was investigated by use of sodium carbonate and calcium carbonate. pH changes in the anode and the cathode compartments were controlled by use of buffer solutions. The results of the investigation showed that for the fully saturated clayey soil spiked with nickel had an average removal efficiency of 64%, and the average removal efficiency was 46% for the unsaturated clayey soil. For the sandy soil, the average removal efficiency of Nickel was 90%. Test results showed that presence of carbonates in the remediated soils retarded the clean-up process of nickel-contaminated soils (removal efficiency was reduced from 90% to 60%). EDTA enhanced decontamination of nickel contaminated clayey and sandy soils with carbonates was studied. The average removal efficiency increased from 60% (prior to using EDTA) to more than 90% after using EDTA.

Keywords: buffer solution, EDTA, electroremediation, nickel removal efficiency

Procedia PDF Downloads 184

Authors: Vasilis Andriopoulos, Maria D. Gkioni, Elena Koutra, Savvas G. Mastropetros, Fotini N. Lamari, Sofia Hatziantoniou, Michalis Kornaros

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In the present study, the antioxidant activity of aqueous and methanolic extracts of Chlorella minutissima, Dunaliella salina, Isochrysis galbana, Nannochloropsis oculata and Tisohrysis lutea, as well as the proximate composition and fatty acid profile were evaluated, with the aim to select species suitable for co-production of antioxidants and aquaculture feed. Batch cultivation was performed at 25oC in a modified f/2 medium under continuous illumination and aeration with ambient air. Biomass was collected via centrifugation and extracted first with H2O and subsequently with methanol at two growth phases (early and late stationary). Total phenolic content and antioxidant and reducing activity of the extracts were evaluated. The highest phenolic content was found in the methanolic extract of C. minutissima at the early stationary phase (9.04±0.68 mg Gallic Acid Equivalent g-1 dry weight), and the aqueous extract of D. salina at the late stationary phase (8.78±1.49 mg Gallic Acid Equivalent g-1 Dry weight). Antioxidant activity, measured as 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, and Ferric reducing antioxidant power assay of methanolic extracts were comparable to the literature and correlated to Total phenolic content and Chlorophyll content of the biomass. No such correlation was found in the aqueous extracts. N. oculata and T. lutea were high in protein (39.88±1.72% Dry weight and 43.30±1.33% Dry weight, respectively) and carotenoids (0.64±0.13% and 0.92±0.02%, respectively). Additionally, they presented high eicosapentaenoic acid and docosahexaenoic acid levels (33.74±9.98 mg eicosapentaenoic acid g-1 DW and 31.31±2.92 mg docosahexaenoic acid g-1 dry weight, respectively). N. oculata and T. lutea are promising candidates for the co-production of antioxidants and aquaculture feed, while C. minutissima and D. salina showed promise due to their higher antioxidant content.

Keywords: aquaculture fee, antioxidant activity, fatty acids, microalgae, total phenolic content

Procedia PDF Downloads 169

Authors: Figen Kadirgan, M. A. Neset Kadirgan, Gokcen A. Ciftcioglu

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Addressing food security and climate change challenges have to be done in an integrated manner. To increase food production and to reduce emissions intensity, thus contributing to mitigate climate change, food systems have to be more efficient in the use of resources. To ensure food security and adapt to climate change they have to become more resilient. The changes required in agricultural and food systems will require the creation of supporting institutions and enterprises to provide services and inputs to smallholders, fishermen and pastoralists, and transform and commercialize their production more efficiently. Thus there is continously growing need to switch to green economy where simultaneously causes reduction in carbon emissions and pollution, enhances energy and resource-use efficiency; and prevents the loss of biodiversity and ecosystem services. Smart Agriculture takes into account the four dimensions of food security, availability, accessibility, utilization, and stability. It is well known that, the increase in world population will strengthen the population-food imbalance. The emphasis on reduction of food losses makes a point on production, on farmers, on increasing productivity and income ensuring food security. Where also small farmers enhance their income and stabilize their budget. The use of solar drying for agricultural, marine or meat products is very important for preservation. Traditional sun drying is a relatively slow process where poor food quality is seen due to an infestation of insects, enzymatic reactions, microorganism growth and micotoxin development. In contrast, solar drying has a sound solution to all these negative effects of natural drying and artificial mechanical drying. The technical directions in the development of solar drying systems for agricultural products are compact collector design with high efficiency and low cost. In this study, using solar selective surface produced in Selektif Teknoloji Co. Inc. Ltd., solar dryers with high efficiency will be developed and a feasibility study will be realized.

Keywords: energy, renewable energy, solar collector, solar drying

Procedia PDF Downloads 225

Authors: Aasim Siddiqui

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In a country where 45.6 per cent of the total population lives below the poverty line, according to the Human Development Report 2014 by UNDP, an increasing number of private companies are now dedicating their resources to remedy this situation of chronic poverty. Most corporations in Pakistan now have a separate and dedicated department for Corporate Social Responsibility (CSR), albeit with varying goals and hence different strategies for achieving those goals. Similarly, Marine Group of Companies (MRGC) also has a robust CSR policy which the group implements through a Non-Government Organization (NGO) called Organization for Social Development Initiatives (OSDI). This organization, which operates under the ambit of MRGC’s CSR division, has a concentrated focus on helping the poorest communities in the rural areas of Pakistan to break out of intergenerational poverty. This paper maps the theoretical strategies as well as practical activities undertaken by OSDI for poverty alleviation via rural development in Pakistan. To obtain in-depth information of demographics, livelihood and socio-economic indicators in OSDI’s focused districts; a combination of quantitative and qualitative research methodologies was used during the course of this research. The paper highlights and explains OSDI’s unique three-pronged approach which aims at reducing poverty through income generation via the livelihood assistance program and through the provision of access to the most basic services (including health and education) via the community development and food security programs. Modeled on the concept of capacity building, OSDI’s modus operandi is centered on disbursing timely microcredit facilities to farmers who can benefit from these funds by investing in productive assets to foster financial capability for the future. With a focus on increasing the income of poor farmers, OSDI’s approach is to integrate all the socio-economic facets: education, health and sanitation and food security, to induce a sustained positive impact on their living standards.

Keywords: CSR, poverty, rural, sustainability

Procedia PDF Downloads 246

Authors: Nabeel M. Alikunhi, Zenon B. Batang, Aymen Charef, Abdulaziz M. Al-Suwailem

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Saudi Arabia has a long history of using traps as a traditional fishing gear for catching commercially important demersal, mainly coral reef-associated fish species. Fish traps constitute the dominant small-scale fisheries in Saudi waters of Arabian Gulf (eastern seaboard of Saudi Arabia). Recently, however, traps have been increasingly used along the Saudi Red Sea coast (western seaboard), with a coastline of 1800 km (71%) compared to only 720 km (29%) in the Saudi Gulf region. The production trend for traps indicates a recent increase in catches and percent contribution to traditional fishery landings, thus ascertaining the rapid proliferation of trap fishing along the Saudi Red Sea coast. Reef-associated fish species, mainly groupers (Serranidae), emperors (Lethrinidae), parrotfishes (Scaridae), scads and trevallies (Carangidae), and snappers (Lutjanidae), dominate the trap catches, reflecting the reef-dominated shelf zone in the Red Sea. This ongoing investigation covers following major objectives (i) Baseline studies to characterize trap fishery through landing site visit and interview surveys (ii) Stock assessment by fisheries and biological data obtained through monthly landing site monitoring using fishery operational model by FLBEIA, (iii) Operational impacts, derelict traps assessment and by-catch analysis through bottom-mounted video camera and onboard monitoring (iv) Elucidation of fishing grounds and derelict traps impacts by onboard monitoring, Remotely Operated underwater Vehicle and Autonomous Underwater Vehicle surveys; and (v) Analysis of gear design and operations which covers colonization and deterioration experiments. The progress of this investigation on the impacts of the trap fishery on fish stocks and the marine environment in the Saudi Red Sea region is presented.

Keywords: red sea, Saudi Arabia, fish trap, stock assessment, environmental impacts

Procedia PDF Downloads 350

Authors: Geminne Manzano, Clairecynth Yu, Lilibeth Salvador-Reyes, Viviene Santiago, Porfirio AliñO

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The distribution and abundance patterns of many marine sessile organisms such as sponges vary among and within reefs. Determining the factors affecting its distribution is essential especially for organisms that produce secondary metabolites with pharmaceutical importance. In this study, the small-scale distribution patterns of the Philippine blue sponge, Xestospongia sp. in relation to some ecological factors were examined. The relationship between the renieramycin-M production and their benthic attributes were also determined. Ecological surveys were conducted on two stations with varying depth and exposure located in Oriental Mindoro, Philippines. Three 30 by 6m belt transect were used to assess the sponge abundance at each station. The substratum of the sponges was also characterized. Fish visual census observations were also taken together with the photo transect methods benthic surveys. Sponge samples were also collected for the extraction of Renieramycin-M and for further chemical analysis. Varying distribution patterns were observed to be attributed to the combination of different ecological and environmental factors. The amount of Renieramycin-production also varied in each station. The common substratum for blue sponges includes hard and soft corals, as well as, dead coral with algal patches. Blue sponges from exposed habitat frequently grow associated with massive and branching corals, Porites sp., while the most frequent substrate found on sheltered habitats is the coral Pavona sp. Exploring the influence of ecological and environmental parameters on the abundance and distribution of sponge assemblages provide ecological insights and their potential applications to pharmaceutical studies. The results of this study provide further impetus in pursuing studies into patterns and processes of the Philippine blue sponge, Xestospongia sp. distribution in relation to the chemical ecology of its secondary metabolites.

Keywords: distribution patterns, Porifera, Renieramycin-M, sponge assemblages, Xestospongia sp.

Procedia PDF Downloads 266

Authors: Belinda Vega, Claudio Alvarez, Héctor Flores, Marcia Oliva, Katherine Alveal, Teresa Toro, María José Tapia, Fanny Guzmán

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With the increase in global temperatures and the decrease of oxygen (O2) concentration in the oceans, fish cultures are exposed to frequent fluctuations in dissolved O2 (DO) concentration that can cause chronic stress in the animals, altering the normal functioning of their immune system and making them vulnerable to infections, consequently increasing morbidity and mortality in the farms with economic losses. The mucosal organs (skin -and mucus-, gills, gut, and nasal mucosa) are the first line of defense of the fish against pathogens. Therefore, the objective of this study is to evaluate the effect of hypoxia on the antimicrobial activity of epidermal mucus from corvina drum (Cilus Gilberti), a native marine species with the potential for the diversification of aquaculture in Chile. To achieve this, the epidermal mucus of juveniles (~220g) kept under normoxia (7 mg/L DO) and hypoxia (2 mg/L DO) environmental conditions was collected after 6 weeks, as well as after 6 days of intraperitoneal inoculation with lipopolysaccharide from Vibrio anguillarum to induce an immune response in the fish. Total protein extracts of the mucus were used for bactericidal activity and lysozyme and peroxidase activity assays. Although the mucus from both experimental groups showed inhibitory effects on the bacterial growth of Vibrio anguillarum and Vibrio ordalli, this effect was more long-lasting in the normoxia group. We also observed a notable reduction in the presence of lysozyme in the mucus from fish exposed to hypoxia, with no differences in peroxidase content. Future proteomic studies of corvina mucus associated with the environmental conditions studied in this work will allow the isolation and identification of peptides with antimicrobial activity, those responsible for the results obtained. This will help establish strategies aimed at minimizing the impacts of hypoxia on the defense responses of corvina drum against potential pathogens. Funding: FONDECYT 3200440 and FONDECYT 1210056

Keywords: Cilus gilberti, mucus, antimicrobial activity, HYPOXIA

Procedia PDF Downloads 75

Authors: Manu Manu, Pardha J. Saradhi, Ramana M. V. Murthy

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Wind Energy is accepted as one of the most developed, cost effective and proven renewable energy technologies to meet increasing electricity demands in a sustainable manner. Preliminary assessment studies along Indian Coastline by Ministry of New and Renewable Energy have indicated prospects for development of offshore wind power along Tamil Nadu Coast, India. The commercial viability of a wind project mainly depends on wind characteristics on site. Hence, it is internationally recommended to perform site-specific wind resource assessment based on two years’ wind profile as a part of the feasibility study. Conventionally, guy wire met mast are used onshore for the collection of wind profile. Installation of similar structure in offshore requires complex marine spread and are very expensive. In the present study, an attempt is made to develop 120 m long lattice tower supported on the jacket, piled to the seabed at Rameshwaram, Tamil Nadu, India. Offshore met-masts are subjected to combined wind and hydrodynamic loads, and these lateral loads should be safely transferred to soil. The wind loads are estimated based on gust factor method, and the hydrodynamic loads are estimated by Morison’s equation along with suitable wave theory. The soil is modeled as three nonlinear orthogonal springs based on API standards. The structure configuration and optimum member sizes are obtained for extreme cyclone events. The dynamic behavior of mast under coupled wind and wave loads is also studied. The static responses of a mast with jacket type offshore platform have been studied using a frame model in SESAM. It is found from the study that the maximum displacement at the top of the mast for the random wave is 0.003 m and that of the tower for wind is 0.08 m during the steady state. The dynamic analysis results indicate that the structure is safe against coupled wind and wave loading.

Keywords: offshore wind, mast, static, aerodynamic load, hydrodynamic load

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Authors: Nikhil Kumar, Asish Bandyopadhyay

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Laser welding process is a capable technology for forming the automobile, microelectronics, marine and aerospace parts etc. In the present work, a mathematical and statistical approach is adopted to study the laser welding of AISI 304 stainless steel. A robotic control 500 W pulsed Nd:YAG laser source with 1064 nm wavelength has been used for welding purpose. Butt joints are made. The effects of welding parameters, namely; laser power, scanning speed and pulse width on the seam width and depth of penetration has been investigated using the empirical models developed by response surface methodology (RSM). Weld quality is directly correlated with the weld geometry. Twenty sets of experiments have been conducted as per central composite design (CCD) design matrix. The second order mathematical model has been developed for predicting the desired responses. The results of ANOVA indicate that the laser power has the most significant effect on responses. Microstructural analysis as well as hardness of the selected weld specimens has been carried out to understand the metallurgical and mechanical behaviour of the weld. Average micro-hardness of the weld is observed to be higher than the base metal. Higher hardness of the weld is the resultant of grain refinement and δ-ferrite formation in the weld structure. The result suggests that the lower line energy generally produce fine grain structure and improved mechanical properties than the high line energy. The combined effects of input parameters on responses have been analyzed with the help of developed 3-D response surface and contour plots. Finally, multi-objective optimization has been conducted for producing weld joint with complete penetration, minimum seam width and acceptable welding profile. Confirmatory tests have been conducted at optimum parametric conditions to validate the applied optimization technique.

Keywords: ANOVA, laser welding, modeling and optimization, response surface methodology

Procedia PDF Downloads 294