Search results for: dispersed generation (DG)

Authors: Vinay Kumar Vanjakula, Frank Adam

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The generation of electricity through wind power is one of the leading renewable energy generation methods. Due to abundant higher wind speeds far away from shore, the construction of offshore wind turbines began in the last decades. However, the installation of offshore foundation-based (monopiles) wind turbines in deep waters are often associated with technical and financial challenges. To overcome such challenges, the concept of floating wind turbines is expanded as the basis of the oil and gas industry. For such a floating system, stabilization in harsh conditions is a challenging task. For that, a robust heavy-weight gravity anchor is needed. Transportation of such anchor requires a heavy vessel that increases the cost. To lower the cost, the gravity anchor is designed with ballast chambers that allow the anchor to float while towing and filled with water when lowering to the planned seabed location. The presence of such a large structure may influence the flow field around it. The changes in the flow field include, formation of vortices, turbulence generation, waves or currents flow breaking and pressure differentials around the seabed sediment. These changes influence the installation process. Also, after installation and under operating conditions, the flow around the anchor may allow the local seabed sediment to be carried off and results in Scour (erosion). These are a threat to the structure's stability. In recent decades, rapid developments of research work and the knowledge of scouring on fixed structures (bridges and monopiles) in rivers and oceans have been carried out, and very limited research work on scouring around a bluff-shaped gravity anchor. The objective of this study involves the application of different numerical models to simulate the anchor towing under waves and calm water conditions. Anchor lowering involves the investigation of anchor movements at certain water depths under wave/current. The motions of anchor drift, heave, and pitch is of special focus. The further study involves anchor scour, where the anchor is installed in the seabed; the flow of underwater current around the anchor induces vortices mainly at the front and corners that develop soil erosion. The study of scouring on a submerged gravity anchor is an interesting research question since the flow not only passes around the anchor but also over the structure that forms different flow vortices. The achieved results and the numerical model will be a basis for the development of other designs and concepts for marine structures. The Computational Fluid Dynamics (CFD) numerical model will build in OpenFOAM and other similar software.

Keywords: anchor lowering, anchor towing, gravity anchor, computational fluid dynamics, scour

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Authors: Anton G. Kalmykov, Andrew Yu. Bychkov, Georgy A. Kalmykov

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Nowadays, most oil reserves in Russia and all over the world are hard to recover. That is the reason oil companies are searching for new sources for hydrocarbon production. One of the sources might be high-carbon formations with unconventional reservoirs. Bazhenov formation is a huge source rock formation located in West Siberia, which contains unconventional reservoirs on some of the areas. These reservoirs are formed by secondary processes with low predicting ratio. Only one of five wells is drilled through unconventional reservoirs, in others kerogen has low thermal maturity, and they are of low petroliferous. Therefore, there was a request for tertiary methods for in-situ cracking of kerogen and production of oil. Laboratory experiments of Bazhenov formation rock hydrous pyrolysis were used to investigate features of the oil generation process. Experiments on Bazhenov rocks with a different mineral composition (silica concentration from 15 to 90 wt.%, clays – 5-50 wt.%, carbonates – 0-30 wt.%, kerogen – 1-25 wt.%) and thermal maturity (from immature to late oil window kerogen) were performed in a retort under reservoir conditions. Rock samples of 50 g weight were placed in retort, covered with water and heated to the different temperature varied from 250 to 400°C with the durability of the experiments from several hours to one week. After the experiments, the retort was cooled to room temperature; generated hydrocarbons were extracted with hexane, then separated from the solvent and weighted. The molecular composition of this synthesized oil was then investigated via GC-MS chromatography Characteristics of rock samples after the heating was measured via the Rock-Eval method. It was found, that the amount of synthesized oil and its composition depending on the experimental conditions and composition of rocks. The highest amount of oil was produced at a temperature of 350°C after 12 hours of heating and was up to 12 wt.% of initial organic matter content in the rocks. At the higher temperatures and within longer heating time secondary cracking of generated hydrocarbons occurs, the mass of produced oil is lowering, and the composition contains more hydrocarbons that need to be recovered by catalytical processes. If the temperature is lower than 300°C, the amount of produced oil is too low for the process to be economically effective. It was also found that silica and clay minerals work as catalysts. Selection of heating conditions allows producing synthesized oil with specified composition. Kerogen investigations after heating have shown that thermal maturity increases, but the yield is only up to 35% of the maximum amount of synthetic oil. This yield is the result of gaseous hydrocarbons formation due to secondary cracking and aromatization and coaling of kerogen. Future investigations will allow the increase in the yield of synthetic oil. The results are in a good agreement with theoretical data on kerogen maturation during oil production. Evaluated trends could be tooled up for in-situ oil generation by shale rocks thermal action.

Keywords: Bazhenov formation, fossil fuels, hydropyrolysis, synthetic oil

Procedia PDF Downloads 114

Authors: Wisam H. Benamer, Ehab A. Elfallah, Mohamed A. Elshaari, Farag A. Elshaari

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A challenge for laboratories is to provide bacterial identification and antibiotic sensitivity results within a short time. Hence, advancement in the required technology is desirable to improve timing, accuracy and quality. Even with the current advances in methods used for both phenotypic and genotypic identification of bacteria the need is there to develop method(s) that enhance the outcome of bacteriology laboratories in accuracy and time. The hypothesis introduced here is based on the assumption that the chromosome of any bacteria contains unique sequences that can be used for its identification and typing. The outcome of a pilot study designed to test this hypothesis is reported in this manuscript. Methods: The complete chromosome sequences of several bacterial species were downloaded to use as search targets for unique sequences. Visual basic and SQL server (2014) were used to generate a complete set of 18-base long primers, a process started with reverse translation of randomly chosen 6 amino acids to limit the number of the generated primers. In addition, the software used to scan the downloaded chromosomes using the generated primers for similarities was designed, and the resulting hits were classified according to the number of similar chromosomal sequences, i.e., unique or otherwise. Results: All primers that had identical/similar sequences in the selected genome sequence(s) were classified according to the number of hits in the chromosomes search. Those that were identical to a single site on a single bacterial chromosome were referred to as unique. On the other hand, most generated primers sequences were identical to multiple sites on a single or multiple chromosomes. Following scanning, the generated primers were classified based on ability to differentiate between medically important bacterial and the initial results looks promising. Conclusion: A simple strategy that started by generating primers was introduced; the primers were used to screen bacterial genomes for match. Primer(s) that were uniquely identical to specific DNA sequence on a specific bacterial chromosome were selected. The identified unique sequence can be used in different molecular diagnostic techniques, possibly to identify bacteria. In addition, a single primer that can identify multiple sites in a single chromosome can be exploited for region or genome identification. Although genomes sequences draft of isolates of organism DNA enable high throughput primer design using alignment strategy, and this enhances diagnostic performance in comparison to traditional molecular assays. In this method the generated primers can be used to identify an organism before the draft sequence is completed. In addition, the generated primers can be used to build a bank for easy access of the primers that can be used to identify bacteria.

Keywords: bacteria chromosome, bacterial identification, sequence, primer generation

Procedia PDF Downloads 193

Authors: Bambi Ward

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Children of Holocaust survivors have been described as inheriting their parents’ trauma as a result of ‘vicarious memory’. The term refers to a process whereby second generation Holocaust survivors subconsciously remember aspects of Holocaust trauma, despite not having directly experienced it. This can occur even when there has been a conspiracy of silence in which survivors chose not to discuss the Holocaust with their children. There are still people born in various parts of the world such as Poland, Hungary, other parts of Europe, USA, Canada and Australia, who have only learnt of their Jewish roots as adults. This discovery may occur during a parent’s deathbed confession, or when an adult child is sorting through the personal belongings of a deceased family member. Some Holocaust survivors chose to deny their Jewish heritage and raise their children as Christians. Reasons for this decision include the trauma experienced during the Holocaust for simply being Jewish, the existence of anti-Semitism, and the desire to protect one’s self and one’s family. Although there has been considerable literature written about the transgenerational impact of trauma on children of Holocaust survivors, there has been little scholarly investigation into the effects of a hidden Jewish identity on these children. This paper presents a case study of an adult child of Hungarian Holocaust survivors who was raised as a Christian. At the age of eight she was told about her family’s Jewish background, but her parents insisted that she keep this a secret, even if asked directly. She honoured their request until she turned forty. By that time she had started the challenging process of reclaiming her Jewish identity. The paper outlines the tension between family loyalty and individual freedom, and discusses the role that art and art therapy played in assisting the subject of the case study to reclaim her Jewish identity and commence writing a memoir about her spiritual journey. The main methodology used in this case study is creative practice-led research. Particular attention is paid to the utilisation of an autoethnographic approach. The autoethnographic tools used include reflective journals of the subject of the case study. These journals reflect on the subject’s collection of autobiographical data relating to her family history, and include memories, drawings, products of art therapy, diaries, letters, photographs, home movies, objects, and oral history interviews with her mother. The case study illustrates how art and art therapy benefitted a second generation Holocaust survivor who was brought up having to suppress her Jewish identity. The process allowed her to express subconscious thoughts and feelings about her identity and free herself from the burden of the long term secret she had been carrying. The process described may also be of assistance to other traumatised people who have been trying to break the silence and who are seeking to express themselves in a positive and healing way.

Keywords: art, hidden identity, holocaust, silence

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Authors: Muhammad Shoaib, Hassan M. Al-Swaidan

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Air pollution has been a major challenge for the scientists today, due to the release of toxic emissions from various industries like power plants, desalination plants, industrial processes and transportation vehicles. Harmful emissions into the air represent an environmental pressure that reflects negatively on human health and productivity, thus leading to a real loss in the national economy. Variety of air pollutants in the form of carbon oxides, hydrocarbons, nitrogen oxides, sulfur oxides, suspended particulate material etc. are present in air due to the combustion of different types of fuels like crude oil, diesel oil and natural gas. Among various pollutants, NOx and SOx emissions are considered as highly toxic due to its carcinogenicity and its relation with various health disorders. In Kingdom of Saudi Arabia electricity is generated by burning of crude, diesel or natural gas in the turbines of electricity stations. Out of these three, crude oil is used extensively for electricity generation. Due to the burning of the crude oil there are heavy contents of gaseous pollutants like sulfur dioxides (SOx) and nitrogen oxides (NOx), gases which are ultimately discharged in to the environment and is a serious environmental threat. The breakthrough point in case of lab studies using 1 gm of sliced activated carbon adsorbant comes after 20 and 30 minutes for NOx and SOx, respectively, whereas in case of PP8 plant breakthrough point comes in seconds. The saturation point in case of lab studies comes after 100 and 120 minutes and for actual PP8 plant it comes after 60 and 90 minutes for NOx and SOx adsorption, respectively. Surface characterization of NOx and SOx adsorption on SAC confirms the presence of peaks in the FT-IR spectrum. CHNS study verifies that the SAC is suitable for NOx and SOx along with some other C and H containing compounds coming out from stack emission stream from the turbines of a power plant.

Keywords: activated carbon, flue gases, NOx and SOx adsorption, physical activation, power plants

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Authors: Heba Gamal Abd Elhaleem Elsayed, Nour F Attia

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The extensive use of textile and textile based materials in various applications including industrial applications are increasing regularly due to their interesting properties which require rapid development in their functions to be adapted to these applications [1-3]. Herein, green, new and renewable smart coating was developed for furniture textile fabrics. Facile and single step method was used for synthesis of green coating based on mandarin peel and chitosan. As, the mandarin peel as fruit waste material was dried, grinded and directly dispersed in chitosan solution producing new green coating composite and then coated on textile fabrics. The mass loadings of green mandarin peel powder was varied on 20-70 wt% and optimized. Thermal stability of coated textile fabrics was enhanced and char yield was improved compared to uncoated one. The charring effect of mandarin peel powder coated samples was significantly enhanced anticipating good flame retardancy effect. The tensile strength of the coated textile fabrics was improved achieved 35% improvement compared to uncoated sample. The interaction between the renewable coating and textile was evaluated. The morphology of uncoated and coated textile fabrics was studied using microscopic technique. Additionally, based on thermal properties of mandarin peel powder it could be promising flame retardant for textile fabrics. This study open new avenues for finishing textile fabrics with enhanced thermal, flame retardancy and mechanical properties with cost-effective and renewable green and effective coating

Keywords: flame retardant , Thermal Properties, Textile Coating , Renewable Textile

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Authors: Ayten Bakhtiyar Khasayeva

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Lower Kura depression is a part of the South Caspian Basin (SCB), located between the folded regions of the Greater and Lesser Caucasus. The region is characterized by thick sedimentary cover 22 km (SCB up to 30 km), high sedimentation rate, low geothermal gradient (average value corresponds to 2 °C / 100m). There is Quaternary, Pliocene, Miocene and Oligocene deposits take part in geological structure. Miocene and Oligocene deposits are opened by prospecting and exploratory wells in the areas of Kalamaddin and Garabagli. There are 25 mud volcanoes within the territory of the Lower Kura depression, which are the unique source of information about hydrocarbons contenting great depths. During the wells data research, solid erupted products and mud volcano fluids, and according to the geological and thermal characteristics of the region, it was determined that the main phase of the hydrocarbon generation (MK1-AK2) corresponds to a wide range of depths from 10 to 14 km, which corresponds to the Pliocene-Miocene sediments, and to the "oil and gas windows" according to the intended meaning of R0 ≈ 0,65-0,85%. Fluids of mud volcanoes comprise by the following phases - gas, water. Gas phase consists mainly of methane (99%) of heavy hydrocarbons (С2+ hydrocarbons), CO2, N2, inert components He, Ar. The content of the С2+ hydrocarbons in the gases of mud volcanoes associated with oil deposits is increased. Carbon isotopic composition of methane for the Lower Kura depression varies from -40 ‰ to -60 ‰. Water of mud volcanoes are represented by all four genetic types. However the most typical types of water are HCN type. According to the Mg-Li geothermometer formation of mud waters corresponds to the temperature range from 20 °C to 140 °C (PC2). The solid product emissions of mud volcanoes identified 90 minerals and 30 trace elements. As a result geochemical investigation, thermobaric and geological conditions, zone oil and gas generation - the prospect of the Lower Kura depression is projected to depths greater than 10 km.

Keywords: geology, geochemistry, mud volcanoes, petroleum potential

Procedia PDF Downloads 367

Authors: H. K. Shahzad, M. A. Hussein, F. Patel, N. Al-Aqeeli, T. Laoui

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The purpose of the present study was to use the adsorption mechanism with microfiltration synergistically for efficient heavy metal removal from contaminated water. Alumina (Al2O3) is commonly used for ceramic membranes development while recently carbon nanotubes (CNTs) have been considered among the best adsorbent materials for heavy metals. In this work, we combined both of these materials to prepare porous Al2O3-CNTs nanocomposite membranes via Spark Plasma Sintering (SPS) technique. Alumina was used as a base matrix while CNTs were added as filler. The SPS process parameters i.e. applied pressure, temperature, heating rate, and holding time were varied to obtain the best combination of porosity (64%, measured according to ASTM c373-14a) and strength (3.2 MPa, measured by diametrical compression test) of the developed membranes. The prepared membranes were characterized using X-ray diffraction (XRD), field emission secondary electron microscopy (FE-SEM), contact angle and porosity measurements. The results showed that properties of the synthesized membranes were highly influenced by the SPS process parameters. FE-SEM images revealed that CNTs were reasonably dispersed in the alumina matrix. The porous membranes were evaluated for their water flux transport as well as their capacity to adsorb heavy metals ions. Selected membranes were able to remove about 97% cadmium from contaminated water. Further work is underway to enhance the removal efficiency of the developed membranes as well as to remove other heavy metals such as arsenic and mercury.

Keywords: heavy metal removal, inorganic membrane, nanocomposite, spark plasma sintering

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Authors: Patricia Jayshree Jacob, Mas Jaffri Masarudinb, Mohd Zobir Hussein, Raha Abdul Rahim

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Iron based ferromagnetic nanoparticles (IONP) and silver nanostructures (AgNP) have found a wide range of application in antimicrobial therapy, cell targeting, and environmental applications. As such, the design of well-defined monodisperse IONPs and AgNPs have become an essential tool in nanotechnology. Fabrication of these nanostructures using conventional methods is not environmentally conducive and weigh heavily on energy and outlays. Selected microorganisms possess the innate ability to reduce metallic ions in colloidal aqueous solution to generate nanoparticles. Hence, harnessing this potential is a way forward in constructing microbial nano-factories, capable of churning out high yields of well-defined IONP’s and AgNP's with physicochemical characteristics on par with the best synthetically produced nanostructures. In this paper, we report the isolation and characterization of bacterial strains isolated from the tropical marine and freshwater ecosystems of Malaysia that demonstrated facile and rapid generation of ferromagnetic nanoparticles and silver nanostructures when precursors such as FeCl₃.6H₂O and AgNO₃ were added to the cell-free bacterial lysate in colloidal solution. Characterization of these nanoparticles was carried out using FESEM, UV Spectrophotometer, XRD, DLS and FTIR. This aerobic bioprocess was carried out at ambient temperature and humidity and has the potential to be developed for environmental friendly, cost effective large scale production of IONP’s. A preliminary bioprocess study on the harvesting time, incubation temperature and pH was also carried out to determine pertinent abiotic parameters contributing to the optimal production of these nanostructures.

Keywords: iron oxide nanoparticles, silver nanoparticles, biosynthesis, aquatic bacteria

Procedia PDF Downloads 285

Authors: Mohsin Raza, Rizwan Latif, Syed Adnan Qasim, Imran Shafi

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High torque low-speed diesel engine has a wide range of industrial and commercial applications. In literature, it’s found that lot of work has been done for the high-speed diesel engine and research on High Torque low-speed is rare. The fuel injection plays a key role in the efficiency of engine and reduction in exhaust emission. The fuel breakup plays a critical role in air-fuel mixture and spray combustion. The current study explains numerically an important phenomenon in spray combustion which is deformation and breakup of liquid drops in compression ignition internal combustion engine. The secondary breakup and its influence on spray and characteristics of compressed gas in-cylinder have been calculated by using simulation software in the backdrop of high torque low-speed diesel like conditions. The secondary spray breakup is modeled with KH - RT instabilities. The continuous field is described by turbulence model and dynamics of the dispersed droplet is modeled by Lagrangian tracking scheme. The results by using KH - RT model are compared against other default methods in OpenFOAM and published experimental data from research and implemented in CFD (Computational Fluid Dynamics). These numerical simulation, done in OpenFoam and Matlab, results are analyzed for the complete 720- degree 4 stroke engine cycle at a low engine speed, for favorable agreement to be achieved. Results thus obtained will be analyzed for better evaporation in near nozzle region. The proposed analyses will further help in better engine efficiency, low emission and improved fuel economy.

Keywords: diesel fuel, KH-RT, Lagrangian , Open FOAM, secondary breakup

Procedia PDF Downloads 265

Authors: Matthew Holland, Jason Everett, Martin Cox, Iain Suthers

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High spatial-resolution distribution of planktivorous reef fish can reveal behavioural adaptations to optimise the balance between feeding success and predator avoidance. We used a multi-beam echosounder to record bathymetry and the three-dimensional distribution of fish schools associated with natural and artificial reefs. We utilised generalised linear models to assess the distribution, orientation, and aggregation of fish schools relative to the structure, vertical relief, and currents. At artificial reefs, fish schooled more closely to the structure and demonstrated a preference for the windward side, particularly when exposed to strong currents. Similarly, at natural reefs fish demonstrated a preference for windward aspects of bathymetry, particularly when associated with high vertical relief. Our findings suggest that under conditions with stronger current velocity, fish can exercise their preference to remain close to structure for predator avoidance, while still receiving an adequate supply of zooplankton delivered by the current. Similarly, when current velocity is low, fish tend to disperse for better access to zooplankton. As artificial reefs are generally deployed with the goal of creating productivity rather than simply attracting fish from elsewhere, we advise that future artificial reefs be designed as semi-linear arrays perpendicular to the prevailing current, with multiple tall towers. This will facilitate the conversion of dispersed zooplankton into energy for higher trophic levels, enhancing reef productivity and fisheries.

Keywords: artificial reef, current, forage fish, multi-beam, planktivorous fish, reef fish, schooling

Procedia PDF Downloads 159

Authors: Moaawia Abdulgader Gdara

Abstract:

This work presents a study of Carbone dioxide generation and migration in the Bahi sandstone reservoir over the EPSA 120/136 (conc 72). En Naga Sub Basin, Sirte Basin Libya. The Lower Cretaceous Bahi Sandstone is the result of deposition that occurred between the start of the Cretaceous rifting that formed the area's Horsts, Grabens and Cenomanian marine transgression. Bahi sediments were derived mainly from those Nubian sediments exposed on the structurally higher blocks, transported short distances into newly forming depocenters such as the En Naga Sub-basin and were deposited by continental processes over the Sirte Unconformity (pre-Late Cretaceous surface) Bahi Sandstone facies are recognized in the En Naga Sub-basin within different lithofacies distribution over this sub-base. One of the two lithofacies recognized in the Bahi is a very fine to very coarse, subangular to angular, pebbly and occasionally conglomeratic quartz sandstone, which is commonly described as being compacted but friable. This sandstone may contain pyrite and minor kaolinite. This facies was encountered at 11,042 feet in F1-72 well, and at 9,233 feet in L1-72. Good, reservoir quality sandstones are associated with paleotopographic highs within the sub-basin and around its margins where winnowing and/or deflationary processes occurred. The second Bahi Lithofacies is a thinly bedded sequence dominated by shales and siltstones with subordinate sandstones and carbonates. The sandstones become more abundant with depth. This facies was encountered at 12,580 feet in P1 -72 and at 11,850 feet in G1a -72. This argillaceous sequence is likely the Bahi sandstone's lateral facies equivalent deposited in paleotopographic lows, which received finer-grained material. The Bahi sandstones are generally described as a good reservoir rock, which after prolific production tests for the drilled wells makes Bahi sandstones the principal reservoir rocks for CO₂ where large volumes of CO₂ gas have been discovered in the Bahi Formation on and near EPSA 120/136, (conc 72). CO₂ occurs in this area as a result of the igneous activity of the Al Harouge Al Aswad complex. Igneous extrusive have been pierced in the subsurface and are exposed at the surface. Bahi CO₂ prospectivity is thought to be excellent in the central to western areas of EPSA 120/136 (CONC 72) where there are better reservoir quality sandstones associated with Paleostructural highs. Condensate and gas prospectivity increases to the east as the CO₂ productivity decreases with distance away from the Al Haruj Al Aswad igneous complex. To date, it has not been possible to accurately determine the volume of these strategically valuable reserves, although there are positive indications that they are very large. Three main structures (Barrut I, En Naga A and En Naga O) are thought to be prospective for the lower Cretaceous Bahi sandstone development. These leads are the most attractive on EPSA 120/136 for the deep potential.

Keywords: En Naga Sub Basin, Al Harouge Al Aswad's Igneous complex, carbon dioxide generation, migration in the Bahi sandstone reservoir, lower cretaceous Bahi Sandstone

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Authors: Moaawia Abdulgader Gdara

Abstract:

This work presents a study of carbon dioxide generation and migration in the Bahi sandstone reservoir over the EPSA 120/136 (conc 72), En Naga Sub Basin, Sirte Basin, Libya. The Lower Cretaceous Bahi Sandstone is the result of deposition that occurred between the start of the Cretaceous rifting that formed the area's Horsts, Grabens, and Cenomanian marine transgression. Bahi sediments were derived mainly from those Nubian sediments exposed on the structurally higher blocks, transported short distances into newly forming depocenters such as the En Naga Sub-basin, and were deposited by continental processes over the Sirte Unconformity (pre-Late Cretaceous surface). Bahi Sandstone facies are recognized in the En Naga Sub-basin within different lithofacies distributed over this sub-base. One of the two lithofacies recognized in the Bahi is a very fine to very coarse, subangular to angular, pebbly, and occasionally conglomeratic quartz sandstone, which is commonly described as being compacted but friable. This sandstone may contain pyrite, minor kaolinite. This facies was encountered at 11,042 feet in F1-72 well and at 9,233 feet in L1-72. Good, reservoir quality sandstones are associated with paleotopographic highs within the sub-basin and around its margins where winnowing and/or deflationary processes occurred. The second Bahi Lithofacies is a thinly bedded sequence dominated by shales and siltstones with subordinate sandstones and carbonates. The sandstones become more abundant with depth. This facies was encountered at 12,580 feet in P1 -72 and at 11,850 feet in G1a -72. This argillaceous sequence is likely the Bahi sandstone's lateral facies equivalent deposited in paleotopographic lows, which received finer grained material. The Bahi sandstones are generally described as a good reservoir rock, which after prolific production tests for the drilled wells that makes Bahi sandstones the principal reservoir rocks for CO₂ where large volumes of CO₂ gas have been discovered in the Bahi Formation on and near EPSA 120/136, (conc 72). CO₂ occurs in this area as a result of the igneous activity of the Al Harouge Al Aswad complex. Igneous extrusive have been pierced in the subsurface and are exposed at the surface. Bahi CO₂ prospectivity is thought to be excellent in the central to western areas of EPSA 120/136 (CONC 72), where there are better reservoir quality sandstones associated with Paleostructural highs. Condensate and gas prospectivity increases to the east as the CO₂ prospectivity decreases with distance away from the Al Haruj Al Aswad igneous complex. To date, it has not been possible to accurately determine the volume of these strategically valuable reserves, although there are positive indications that they are very large. Three main structures (Barrut I, En Naga A, and En Naga O) are thought to be prospective for the lower Cretaceous Bahi sandstone development. These leads are the most attractive on EPSA 120/136 for the deep potential.

Keywords: En Naga Sub Basin, Al Harouge Al Aswad’s Igneous Complex, carbon dioxide generation and migration in the Bahi sandstone reservoir, lower cretaceous Bahi sandstone

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Authors: Atif Zafar Khan, Swarnendra Singh, Imrana Naseem

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Breast cancer is one of the most frequent malignancies in women worldwide and a leading cause of cancer-related deaths among women. Therefore, there is a need to identify new chemotherapeutic strategies for cancer treatment. Unlike normal cells, cancer cells contain elevated copper levels which play an integral role in angiogenesis. Copper is an important metal ion associated with the chromatin DNA, particularly with guanine. Thus, targeting copper via copper-specific chelators in cancer cells can serve as effective anticancer strategy. Keeping in view these facts, we evaluated the anticancer activity and copper-dependent cytotoxic effect of coumestrol (phytoestrogen in soybean products) in breast cancer MCF-7 cells. Coumestrol inhibited proliferation and induced apoptosis in MCF-7 cells, which was prevented by copper chelator neocuproine and ROS scavengers. Coumestrol treatment induced ROS generation coupled to DNA fragmentation, up-regulation of p53/p21, cell cycle arrest at G1/S phase, mitochondrial membrane depolarization and caspases 9/3 activation. All these effects were suppressed by ROS scavengers and neocuproine. These results suggest that coumestrol targets elevated copper for redox cycling to generate ROS leading to DNA fragmentation. DNA damage leads to p53 up-regulation which directs the cell cycle arrest at G1/S phase and promotes caspase-dependent apoptosis of MCF-7 cells. In conclusion, coumestrol induces pro-oxidant cell death by chelating cellular copper to produce copper-coumestrol complexes that engages in redox cycling in breast cancer cells. Thus, targeting elevated copper levels might be a potential therapeutic strategy for selective cytotoxic action against malignant cells.

Keywords: apoptosis, breast cancer, copper chelation, coumestrol, reactive oxygens species, redox cycling

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Authors: Szu-Chieh Yu, Pei-Chin Chiand, Chih-Yi Lin, Yi-Wen Chien

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UV radiation from sunlight cause numbers of acute and chronic skin damage which can result in inflammation, immune changes, physical changes and DNA damage that facilitates skin aging and the development of skin carcinogenesis. Reactive oxygen species (ROS) are generated by excessive solar UV radiation, resulting in oxidative damage to cellar components, proteins, lipids, and nucleic acids. Thus, antioxidation plays an important role that protects skin against ROS-induced injury. Safflower (Carthamus tinctorius L.) is an important Chinese medicine contained abundance flavones and hydroxysafflor yellow A (HSYA) which is main active ingredient. HSYA is part of quinochalcone and has unique structures of hydroxy groups that provided the antioxidant effect. In this study, the aim was to investigate the protective role of HYSA in human keratinocytes (HaCaT) against UVA-induced oxidative damage and the possible mechanism. The HaCaT cells were UVA-irradiated and the effects of HYSA on cell viability, reactive oxygen species generation, DNA fragmentation and lipid peroxidation were measured. The mRNA expression of matrix metalloproteinase Ι (MMP Ι), cyclooxygenase-2 (COX-2) were determined by RT-PCR. In this study, UVA exposure lead to decrease in cell viability and increase in reactive oxygen species generation in HaCaT cells. HYSA could effectively increase the viability of HaCaT cells after UVA exposure and protect them from UVA-induced oxidative stress. Moreover, HYSA can reduce inflammation through inhibition the mRNA expression of MMP Ι and COX-2. Our results suggest that HSYA can act as a free radical scavenger while keratinocytes were photodamaged. HYSA could be a useful natural medicine for the protection of epidermal cells from UVA-induced damage and will be developed into products for skin care.

Keywords: HaCaT keratinocytes, hydroxysafflor yellow A (HSYA), MMP Ι, oxidative stress

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Authors: Okpaneje Onyinye Theresa, Ugwu Laeticia Udodiri, Okereke Ngozi Agatha, Okoli Nonso Livinus

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This work is on the synthesis and study of the optical characterization of polyaniline/nickel sulphide nanocomposite. Polyaniline (PANI) and nickel sulphide (NiS) nanoparticles were synthesized by oxidative chemical polymerization and sol-gel method. The polyaniline nickel sulphide nanocomposites with various concentrations of NiS were synthesized by in-situ polymerization of aniline monomer. In each case, the nickel sulphide nanoparticles were uniformly dispersed in the aniline hydrochloride before the initiation of oxidative chemical polymerization using ammonium persulphate. The samples formed were subjected to optical characterization using an ultraviolet (UV)-visible light (VIS) spectrophotometer (model: 756S UV – VIS). Optical analysis of the synthesized nanoparticles and nanocomposites showed absorption of radiation within VIS regions. The Tauc model was used to obtain the optical band gap. Energy band gap values of PANI and NiS were found to be 2.50 eV and 1.95 eV, respectively. PANI/NiSnanocomposites has an energy band gap that decreased from 2.25 eV to 1.90 eV as the amount of NiS increased (from 0.5g to 2.0g). These optical results showed that these nanocomposites are potential materials to be considered in solar cells and optoelectronics devices. The structural analysis confirmed the formation of polyaniline and hexagonal nickel sulphide with an average crystallite size of 25.521 nm, while average crystallite sizes of PANI/NiSnanocomposites ranged from 19.458 nm to 25.108 nm. Average particle sizes obtained from the SEM images ranged from 23.24 nm to 51.88 nm. Compositional results confirmed the presence of desired elements that made up the nanoparticles and nanocomposites.

Keywords: polyaniline, nickel sulphide, polyaniline-nickel sulphide nanocomposite, optical characterization, structural analysis, morphological properties, compositional properties

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Authors: Mohammad Ghiasvand, Babak Khorsandi, Morteza Kolahdoozan

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Under the influence of waves, oil in the sea is subject to vertical scattering in the water column. Scientists' knowledge of how oil is dispersed in the water column is one of the lowest levels of knowledge among other processes affecting oil in the marine environment, which highlights the need for research and study in this field. Therefore, this study investigates the distribution of oil in the water column in a turbulent environment with zero velocity characteristics. Lack of laboratory results to analyze the distribution of petroleum pollutants in deep water for information Phenomenon physics on the one hand and using them to calibrate numerical models on the other hand led to the development of laboratory models in research. According to the aim of the present study, which is to investigate the distribution of oil in homogeneous and isotropic turbulence caused by the oscillating Grid, after reaching the ideal conditions, the crude oil flow was poured onto the water surface and oil was distributed in deep water due to turbulence was investigated. In this study, all experimental processes have been implemented and used for the first time in Iran, and the study of oil diffusion in the water column was considered one of the key aspects of pollutant diffusion in the oscillating Grid environment. Finally, the required oscillation velocities were taken at depths of 10, 15, 20, and 25 cm from the water surface and used in the analysis of oil diffusion due to turbulence parameters. The results showed that with the characteristics of the present system in two static modes and network motion with a frequency of 0.8 Hz, the results of oil diffusion in the four mentioned depths at a frequency of 0.8 Hz compared to the static mode from top to bottom at 26.18, 57 31.5, 37.5 and 50% more. Also, after 2.5 minutes of the oil spill at a frequency of 0.8 Hz, oil distribution at the mentioned depths increased by 49, 61.5, 85, and 146.1%, respectively, compared to the base (static) state.

Keywords: homogeneous and isotropic turbulence, oil distribution, oscillating grid, oil spill

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Authors: Kgaugelo Lekota, Ayesha Hassim, Henriette Van Heerden

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Bacillus anthracis is the causative agent of anthrax that is composed of three genetic groups, namely A, B, and C. Clade-A is distributed world-wide, while sub-clades B has been identified in Kruger National Park (KNP), South Africa. KNP is one of the endemic anthrax regions in South Africa with distinctive genetic diversity. Genomic surveillance of KNP B. anthracis strains was employed on the historical culture collection isolates (n=67) dated from the 1990’s to 2015 using a whole genome sequencing approach. Whole genome single nucleotide polymorphism (SNPs) and pan-genomics analysis were used to define the B. anthracis genetic population structure. This study showed that KNP has heterologous B. anthracis strains grouping in the A-clade with more prominent ABr.005/006 (Ancient A) SNP lineage. The 2012 and 2015 anthrax isolates are dispersed amongst minor sub-clades that prevail in non-stabilized genetic evolution strains. This was augmented with non-parsimony informative SNPs of the B. anthracis strains across minor sub-clades of the Ancient A clade. Pan-genomics of B. anthracis showed a clear distinction between A and B-clade genomes with 11 374 predicted clusters of protein coding genes. Unique accessory genes of B-clade genomes that included biosynthetic cell wall genes and multidrug resistant of Fosfomycin. South Africa consists of diverse B. anthracis strains with unique defined SNPs. The sequenced B. anthracis strains in this study will serve as a means to further trace the dissemination of B. anthracis outbreaks globally and especially in South Africa.

Keywords: bacillus anthracis, whole genome single nucleotide polymorphisms, pangenomics, kruger national park

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Authors: Qiuying Li

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It is a shared opinion that sustainable development requires a system discontinuity, meaning that radical changes in the way we produce and consume are needed. Within this framework there is an emerging understanding that an important contribution to this change can be directly linked to decisions taken in the design phase of products, services and systems. Design schools have therefore to be able to provide design students with a broad knowledge and effective Design for Sustainability tools, in order to enable a new generation of designers in playing an active role in reorienting our consumption and production patterns.

Keywords: design for sustainability, services, systems, materials, ecomaterials

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Authors: Denise Levy, Helen J. Khoury

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Nuclear technology is a controversial issue among a great share of the Brazilian population. Misinformation and common wrong beliefs confuse public’s perceptions and the scientific community is expected to offer a wider perspective on the benefits and risks resulting from ionizing radiation in everyday life. Attentive to the need of new approaches between science and society, the Nuclear Energy Museum, in northeast Brazil, is an initiative created to communicate the growing impact of the beneficial applications of nuclear technology in medicine, industry, agriculture and electric power generation. Providing accessible scientific information, the museum offers a rich learning environment, making use of different educational strategies, such as films, interactive panels and multimedia learning tools, which not only increase the enjoyment of visitors, but also maximize their learning potential. Developed according to modern active learning instructional strategies, multimedia materials are designed to present the increasingly role of nuclear science in modern life, transforming science education into a meaningful learning experience. In year 2016, nine different interactive computer-based activities were developed, presenting curiosities about ionizing radiation in different landmarks around the world, such as radiocarbon dating works in Egypt, nuclear power generation in France and X-radiography of famous paintings in Italy. Feedback surveys have reported a high level of visitors’ satisfaction, proving the high quality experience in learning nuclear science at the museum. The Nuclear Energy Museum is the first and, up to the present time, the only permanent museum in Brazil devoted entirely to nuclear science.

Keywords: nuclear technology, multimedia learning tools, science museum, society and education

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Authors: Tayyaba Azim, Bibi Amina

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The increase in the popularity of opinion mining with the rapid growth in the availability of social networks has attracted a lot of opportunities for research in the various domains of Sentiment Analysis and Natural Language Processing (NLP) using Artificial Intelligence approaches. The latest trend allows the public to actively use the internet for analyzing an individual’s opinion and explore the effectiveness of published facts. The main theme of this research is to account the public opinion on the most crucial and extensively discussed development projects, China Pakistan Economic Corridor (CPEC), considered as a game changer due to its promise of bringing economic prosperity to the region. So far, to the best of our knowledge, the theme of CPEC has not been analyzed for sentiment determination through the ML approach. This research aims to demonstrate the use of ML approaches to spontaneously analyze the public sentiment on Twitter tweets particularly about CPEC. Support Vector Machine SVM is used for classification task classifying tweets into positive, negative and neutral classes. Word2vec and TF-IDF features are used with the SVM model, a comparison of the trained model on manually labelled tweets and automatically generated lexicon is performed. The contributions of this work are: Development of a sentiment analysis system for public tweets on CPEC subject, construction of an automatic generation of the lexicon of public tweets on CPEC, different themes are identified among tweets and sentiments are assigned to each theme. It is worth noting that the applications of web mining that empower e-democracy by improving political transparency and public participation in decision making via social media have not been explored and practised in Pakistan region on CPEC yet.

Keywords: machine learning, natural language processing, sentiment analysis, support vector machine, Word2vec

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Authors: Mark Salisbury

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The arrival of artificially intelligent avatars and the automation they bring is worrying many of us, not only for our livelihood but for the jobs that may be lost to our kids. We worry about what our place will be as human beings in this new economy where much of it will be conducted online in the metaverse – in a network of 3D virtual worlds – working with intelligent machines. The Future of Leadership was written to address these fears and show what our place will be – the right place – in this new economy of AI avatars, automation, and 3D virtual worlds. But to be successful in this new economy, our job will be to bring wisdom to our workplace and the marketplace. And we will use AI avatars and 3D virtual worlds to do it. However, this book is about more than AI and the avatars that we will work with in the metaverse. It’s about building Organizational intelligence (OI) -- the capability of an organization to comprehend and create knowledge relevant to its purpose; in other words, it is the intellectual capacity of the entire organization. To increase organizational intelligence requires a new kind of knowledge worker, a wisdom worker, that requires a new kind of leadership. This book begins your story for how to become a leader of wisdom workers and be successful in the emerging wisdom economy. After this presentation, conference participants will be able to do the following: Recognize the characteristics of the new generation of wisdom workers and how they differ from their predecessors. Recognize that new leadership methods and techniques are needed to lead this new generation of wisdom workers. Apply personal and professional values – personal integrity, belief in something larger than yourself, and keeping the best interest of others in mind – to improve your work performance and lead others. Exhibit an attitude of confidence, courage, and reciprocity of sharing knowledge to increase your productivity and influence others. Leverage artificial intelligence to accelerate your ability to learn, augment your decision-making, and influence others.Utilize new technologies to communicate with human colleagues and intelligent machines to develop better solutions more quickly.

Keywords: metaverse, generative artificial intelligence, automation, leadership, organizational intelligence, wisdom worker

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Authors: Wang-Xi Fan, Yi Ding, Zhong-Dan Tu, Kuo-Shien Huang, Chao-Ming Huang, Jen-Taut Yeh

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Original and/or functionalized activated nanocarbon particles with a quoted specific surface area of 100, 500, 1000 and 1400 m2/g, respectively, were used to investigate the influence of specific surface areas of activated nanocarbon on ultra drawing and ultimate tensile properties of ultrahigh molecular weight polyethylene (UHMWPE), UHMWPE/activated nanocarbon and UHMWPE/ functionalized activated nanocarbon fibers. The specific surface areas of well dispersed functionalized activated nanocarbon in UHMWPE/functionalized activated nanocarbon fibers can positively affect their ultra drawing, orientation, ultimate tensile properties and “micro-fibril” characteristics. Excellent orientation and ultimate tensile properties of UHMWPE/nanofiller fibers can be prepared by ultra drawing the UHMWPE/functionalized activated nanocarbon as-prepared fibers with optimal contents and compositions of functionalized activated nanocarbon. The ultimate tensile strength value of the best prepared UHMWPE/functionalized activated nanocarbon drawn fiber reached 8.0 GPa, which was about 2.86 times of that of the best-prepared UHMWPE drawn fiber prepared in this study. Specific surface area, morphological and Fourier transform infrared analyses of original and functionalized activated nanocarbon and/or investigations of thermal, orientation factor and ultimate tensile properties of as-prepared and/or drawn UHMWPE/functionalized activated nanocarbon fibers were performed to understand the above-improved ultra drawing and ultimate tensile properties of the UHMWPE/functionalized activated nanocarbon fibers.

Keywords: activated nanocarbon, specific surface areas, ultradrawing, ultrahigh molecular weight polyethylene

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Authors: Klaus Peter Scherer, Daniel Knöll, Constantin Rieder

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Problem and Purpose: Intelligent systems are available and helpful to support the human being decision process, especially when complex surgical eye interventions are necessary and must be performed. Normally, such a decision support system consists of a knowledge-based module, which is responsible for the real assistance power, given by an explanation and logical reasoning processes. The interview based acquisition and generation of the complex knowledge itself is very crucial, because there are different correlations between the complex parameters. So, in this project (semi)automated self-learning methods are researched and developed for an enhancement of the quality of such a decision support system. Methods: For ophthalmic data sets of real patients in a hospital, advanced data mining procedures seem to be very helpful. Especially subgroup analysis methods are developed, extended and used to analyze and find out the correlations and conditional dependencies between the structured patient data. After finding causal dependencies, a ranking must be performed for the generation of rule-based representations. For this, anonymous patient data are transformed into a special machine language format. The imported data are used as input for algorithms of conditioned probability methods to calculate the parameter distributions concerning a special given goal parameter. Results: In the field of knowledge discovery advanced methods and applications could be performed to produce operation and patient related correlations. So, new knowledge was generated by finding causal relations between the operational equipment, the medical instances and patient specific history by a dependency ranking process. After transformation in association rules logically based representations were available for the clinical experts to evaluate the new knowledge. The structured data sets take account of about 80 parameters as special characteristic features per patient. For different extended patient groups (100, 300, 500), as well one target value as well multi-target values were set for the subgroup analysis. So the newly generated hypotheses could be interpreted regarding the dependency or independency of patient number. Conclusions: The aim and the advantage of such a semi-automatically self-learning process are the extensions of the knowledge base by finding new parameter correlations. The discovered knowledge is transformed into association rules and serves as rule-based representation of the knowledge in the knowledge base. Even more, than one goal parameter of interest can be considered by the semi-automated learning process. With ranking procedures, the most strong premises and also conjunctive associated conditions can be found to conclude the interested goal parameter. So the knowledge, hidden in structured tables or lists can be extracted as rule-based representation. This is a real assistance power for the communication with the clinical experts.

Keywords: an expert system, knowledge-based support, ophthalmic decision support, self-learning methods

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Authors: M. Stewart, Ameer Al-Khaykan, J. M. Counsell

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Emissions are a consequence of electricity generation. A major option for low carbon generation, local energy systems featuring Combined Heat and Power with solar PV (CHPV) has significant potential to increase energy performance, increase resilience, and offer greater control of local energy prices while complementing the UK’s emissions standards and targets. Recent advances in dynamic modelling and simulation of buildings and clusters of buildings using the IDEAS framework have successfully validated a novel multi-vector (simultaneous control of both heat and electricity) approach to integrating the wide range of primary and secondary plant typical of local energy systems designs including CHP, solar PV, gas boilers, absorption chillers and thermal energy storage, and associated electrical and hot water networks, all operating under a single unified control strategy. Results from this work indicate through simulation that integrated control of thermal storage can have a pivotal role in optimizing system performance well beyond the present expectations. Environmental impact analysis and reporting of all energy systems including CHPV LES presently employ a static annual average carbon emissions intensity for grid supplied electricity. This paper focuses on establishing and validating CHPV environmental performance against conventional emissions values and assessment benchmarks to analyze emissions performance without and with an active thermal store in a notional group of non-domestic buildings. Results of this analysis are presented and discussed in context of performance validation and quantifying the reduced environmental impact of CHPV systems with active energy storage in comparison with conventional LES designs.

Keywords: CHPV, thermal storage, control, dynamic simulation

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Authors: Warda Khan, Remo Lachmann, Adarsh S. Garakahally

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The increasing complexity of software and its applicability in a wide range of industries, e.g., automotive, call for enhanced quality assurance techniques. Test automation is one option to tackle the prevailing challenges by supporting test engineers with fast, parallel, and repetitive test executions. A high degree of test automation allows for a shift from mundane (manual) testing tasks to a more analytical assessment of the software under test. However, a high initial investment of test resources is required to establish test automation, which is, in most cases, a limitation to the time constraints provided for quality assurance of complex software systems. Hence, a computer-aided creation of automated test cases is crucial to increase the benefit of test automation. This paper proposes the application of machine learning for the generation of automated test cases. It is based on supervised learning to analyze test specifications and existing test implementations. The analysis facilitates the identification of patterns between test steps and their implementation with test automation components. For the test case generation, this approach exploits historical data of test automation projects. The identified patterns are the foundation to predict the implementation of unknown test case specifications. Based on this support, a test engineer solely has to review and parameterize the test automation components instead of writing them manually, resulting in a significant time reduction for establishing test automation. Compared to other generation approaches, this ML-based solution can handle different writing styles, authors, application domains, and even languages. Furthermore, test automation tools require expert knowledge by means of programming skills, whereas this approach only requires historical data to generate test cases. The proposed solution is evaluated using various multi-label evaluation criteria (EC) and two small-sized real-world systems. The most prominent EC is ‘Subset Accuracy’. The promising results show an accuracy of at least 86% for test cases, where a 1:1 relationship (Multi-Class) between test step specification and test automation component exists. For complex multi-label problems, i.e., one test step can be implemented by several components, the prediction accuracy is still at 60%. It is better than the current state-of-the-art results. It is expected the prediction quality to increase for larger systems with respective historical data. Consequently, this technique facilitates the time reduction for establishing test automation and is thereby independent of the application domain and project. As a work in progress, the next steps are to investigate incremental and active learning as additions to increase the usability of this approach, e.g., in case labelled historical data is scarce.

Keywords: machine learning, multi-class, multi-label, supervised learning, test automation

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Authors: Tatyana T. Tabakova, Elitsa N. Kolentsova, Dimitar Y. Dimitrov, Krasimir I. Ivanov, Yordanka G. Karakirova, Petya Cv. Petrova, Georgi V. Avdeev

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The catalytic oxidation of CO and volatile organic compounds (VOCs) is considered as one of the most efficient ways to reduce harmful emissions from various chemical industries. The effectiveness of gold-based catalysts for many reactions of environmental significance was proven during the past three decades. The aim of this work was to combine the favorable features of Au and Cu-Ce mixed oxides in the design of new catalytic materials of improved efficiency and economic viability for removal of air pollutants in waste gases from formaldehyde production. Supported oxides of copper and cerium with Cu: Ce molar ratio 2:1 and 1:5 were prepared by wet impregnation of g-alumina. Gold (2 wt.%) catalysts were synthesized by a deposition-precipitation method. Catalysts characterization was carried out by texture measurements, powder X-ray diffraction, temperature programmed reduction and electron paramagnetic resonance spectroscopy. The catalytic activity in the oxidation of CO, CH₃OH and (CH₃)₂O was measured using continuous flow equipment with fixed bed reactor. Both Cu-Ce/alumina samples demonstrated similar catalytic behavior. The addition of gold caused significant enhancement of CO and methanol oxidation activity (100 % degree of CO and CH₃OH conversion at about 60 and 140 ^oC, respectively). The composition of Cu-Ce mixed oxides affected the performance of gold-based samples considerably. Gold catalyst on Cu-Ce/γ-Al₂O₃ 1:5 exhibited higher activity for CO and CH₃OH oxidation in comparison with Au on Cu-Ce/γ-Al₂O₃ 2:1. The better performance of Au/Cu-Ce 1:5 was related to the availability of highly dispersed gold particles and copper oxide clusters in close contact with ceria.

Keywords: CO and VOCs oxidation, copper oxide, Ceria, gold catalysts

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Authors: Zh. Saffari, A. Naeimi, M. S. Ekrami-Kakhki, F. Hamidi

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Fe3O4 is one of the important magnetic oxides with spinel structure; it has exhibited unique electric and magnetic properties based on the electron transfer between Fe2+ and Fe3+ in the octahedral sites. Fe3O4 has received considerable attention in various areas such as cancer therapy, drug targeting, enzyme immobilization catalysis, magnetic cell separation, magnetic refrigeration systems and super-paramagnetic materials Fe3O4–TiO2 nanostructures were synthesized by simple, effective and new co-precipitation method assisted by ultrasonic reaction at room temperatures with organic surfactant. The effect of various parameters such as temperature, time, and power on the size and morphology of the product was investigated. Alternating gradient force magnetometer shows that Fe3O4 nanoparticles exhibit super-paramagnetic behaviour at room temperature. For preparation of nanocomposite, 1 g of TiO2 nanostructures were dispersed in 100 mL of ethanol. 0.25 g of Fe(NO3)2 and 2 mL of octanoic acid was added to the solution as a surfactant. Then, NaOH solution (1.5 M) was slowly added into the solution until the pH of the mixture was 7–8. After complete precipitation, the solution placed under the ultrasonic irradiation for 30 min. The product was centrifuged, washed with distilled water and dried in an oven at 100 °C for 3 h. The resulting red powder was calcinated at 800 °C for 3 h to remove any organic residue. The photocatalytic behaviour of Fe3O4–TiO2 nanoparticles was evaluated using the degradation of a Methyl Violet (MV) aqueous solution under ultraviolet light irradiation. As time increased, more and more MV was adsorbed on the nanoparticles catalyst, until the absorption peak vanish. The MV concentration decreased rapidly with increasing UV-irradiation time

Keywords: magnetic, methyl violet, nanocomposite, photocatalytic

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Authors: Edwin Lerch, Dirk Audring, Cuong Nguyen Mau, Duc Ninh Nguyen, The Cuong Nguyen, The Van Nguyen

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The National Load Dispatch Centre of Electricity Vietnam (EVNNLDC) and Siemens PTI investigated the stability of the electrical 500/220 kV transportation system of Vietnam. The general scope of the investigations is improving the stability of the Vietnam power system and giving the EVNNLDC staff the capability to decide how to deal with expected stability challenges in the future, which are related to the very fast growth of the system. Rapid system growth leads to a very high demand of power transmission from North to South. This was investigated by stability studies of interconnected power system with neighboring countries. These investigations are performed in close cooperation and coordination with the EVNNLDC project team. This important project includes data collection, measurement, model validation and investigation of relevant stability phenomena as well as training of the EVNNLDC staff. Generally, the power system of Vietnam has good voltage and dynamic stability. The main problems are related to the longitudinal system with more power generation in the North and Center, especially hydro power, and load centers in the South of Vietnam. Faults on the power transmission system from North to South risks the stability of the entire system due to a high power transfer from North to South and high loading of the 500 kV backbone. An additional problem is the weak connection to Cambodia power system which leads to interarea oscillations mode. Therefore, strengthening the power transfer capability by new 500kV lines or HVDC connection and balancing the power generation across the country will solve many challenges. Other countermeasures, such as wide area load shedding, PSS tuning and correct SVC placement will improve and stabilize the power system as well. Primary frequency reserve should be increased.

Keywords: dynamic power transmission system studies, blackout prevention, power system interconnection, stability

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Authors: Sushila Jaiswal, Awadhesh Kumar Jaiswal

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Background: Primary melanocytic tumors of the central nervous system (CNS) are uncommon lesions and arise from the melanocytes located within the leptomeninges. Aim and objective: The aim of the study was to evaluate the clinical details, histomorphology of the primary melanocytic tumor of CNS. Method: The study was performed by the retrospective review of the case records of the primary melanocytic tumors of CNS diagnosed in our department. The formalin-fixed, paraffin embedded tissue blocks and tissue sections were retrieved and reviewed. Results: Seven cases (6 males, 1 female; age range- 16-40 years; mean age- 27 years) of primary melanocytic tumors of CNS were retrieved over last seven years. The tumor was intracranial (n=5; frontal – 1 case, parietal – 1 case, cerebello-pontine angle- 1 case, occipital -1 case, foramen magnum-1 case) and intra spinal (n=2; cervical – 2 cases). All patients presented with the neurological deficits related to the location of the tumor. Four cases were malignant melanoma; two were melanocytoma of intermediate grade and remaining one was melanocytoma. On histopathology, melanocytoma and melanoma both displayed sheets of well-differentiated melanocytes having round to oval nuclei with finely dispersed chromatin, occasional single eosinophilic nucleoli and a moderate amount of cytoplasm with abundant granular melanin pigment. The absence of mitosis and macronucleoli was noticed in melanocytoma while melanoma showed frequent mitosis and macronucleoli. On immunohistochemistry, both showed diffuse strong HMB45 and S-100 immunopositivity. Conclusion: Primary melanocytic tumors of CNS are rare and predominantly seen in males. It is important to differentiate melanoma from melanocytoma as prognosis of later is good.

Keywords: melanocytoma, melanoma, brain tumor, melanin

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