Search results for: diesel working process
942 The Impact of Tourism on the Intangible Cultural Heritage of Pilgrim Routes: The Case of El Camino de Santiago
Authors: Miguel Angel Calvo Salve
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This qualitative and quantitative study will identify the impact of tourism pressure on the intangible cultural heritage of the pilgrim route of El Camino de Santiago (Saint James Way) and propose an approach to a sustainable touristic model for these Cultural Routes. Since 1993, the Spanish Section of the Pilgrim Route of El Camino de Santiago has been on the World Heritage List. In 1994, the International Committee on Cultural Routes (CIIC-ICOMOS) initiated its work with the goal of studying, preserving, and promoting the cultural routes and their significance as a whole. Another ICOMOS group, the Charter on Cultural Routes, pointed out in 2008 the importance of both tangible and intangible heritage and the need for a holistic vision in preserving these important cultural assets. Tangible elements provide a physical confirmation of the existence of these cultural routes, while the intangible elements serve to give sense and meaning to it as a whole. Intangible assets of a Cultural Route are key to understanding the route's significance and its associated heritage values. Like many pilgrim routes, the Route to Santiago, as the result of a long evolutionary process, exhibits and is supported by intangible assets, including hospitality, cultural and religious expressions, music, literature, and artisanal trade, among others. A large increase in pilgrims walking the route, with very different aims and tourism pressure, has shown how the dynamic links between the intangible cultural heritage and the local inhabitants along El Camino are fragile and vulnerable. Economic benefits for the communities and population along the cultural routes are commonly fundamental for the micro-economies of the people living there, substituting traditional productive activities, which, in fact, modifies and has an impact on the surrounding environment and the route itself. Consumption of heritage is one of the major issues of sustainable preservation promoted with the intention of revitalizing those sites and places. The adaptation of local communities to new conditions aimed at preserving and protecting existing heritage has had a significant impact on immaterial inheritance. Based on questionnaires to pilgrims, tourists and local communities along El Camino during the peak season of the year, and using official statistics from the Galician Pilgrim’s Office, this study will identify the risk and threats to El Camino de Santiago as a Cultural Route. The threats visible nowadays due to the impact of mass tourism include transformations of tangible heritage, consumerism of the intangible, changes of local activities, loss in the authenticity of symbols and spiritual significance, and pilgrimage transformed into a tourism ‘product’, among others. The study will also approach some measures and solutions to mitigate those impacts and better preserve this type of cultural heritage. Therefore, this study will help the Route services providers and policymakers to better preserve the Cultural Route as a whole to ultimately improve the satisfying experience of pilgrims.Keywords: cultural routes, El Camino de Santiago, impact of tourism, intangible heritage
Procedia PDF Downloads 81941 A Lightweight Interlock Block from Foamed Concrete with Construction and Agriculture Waste in Malaysia
Authors: Nor Azian Binti Aziz, Muhammad Afiq Bin Tambichik, Zamri Bin Hashim
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The rapid development of the construction industry has contributed to increased construction waste, with concrete waste being among the most abundant. This waste is generated from ready-mix batching plants after the concrete cube testing process is completed and disposed of in landfills, leading to increased solid waste management costs. This study aims to evaluate the engineering characteristics of foamed concrete with waste mixtures construction and agricultural waste to determine the usability of recycled materials in the construction of non-load-bearing walls. This study involves the collection of construction wastes, such as recycled aggregates (RCA) obtained from the remains of finished concrete cubes, which are then tested in the laboratory. Additionally, agricultural waste, such as rice husk ash, is mixed into foamed concrete interlock blocks to enhance their strength. The optimal density of foamed concrete for this study was determined by mixing mortar and foam-backed agents to achieve the minimum targeted compressive strength required for non-load-bearing walls. The tests conducted in this study involved two phases. In Phase 1, elemental analysis using an X-ray fluorescence spectrometer (XRF) was conducted on the materials used in the production of interlock blocks such as sand, recycled aggregate/recycled concrete aggregate (RCA), and husk ash paddy/rice husk ash (RHA), Phase 2 involved physical and thermal tests, such as compressive strength test, heat conductivity test, and fire resistance test, on foamed concrete mixtures. The results showed that foamed concrete can produce lightweight interlock blocks. X-ray fluorescence spectrometry plays a crucial role in the characterization, quality control, and optimization of foamed concrete mixes containing construction and agriculture waste. The unique composition mixer of foamed concrete and the resulting chemical and physical properties, as well as the nature of replacement (either as cement or fine aggregate replacement), the waste contributes differently to the performance of foamed concrete. Interlocking blocks made from foamed concrete can be advantageous due to their reduced weight, which makes them easier to handle and transport compared to traditional concrete blocks. Additionally, foamed concrete typically offers good thermal and acoustic insulation properties, making it suitable for a variety of building projects. Using foamed concrete to produce lightweight interlock blocks could contribute to more efficient and sustainable construction practices. Additionally, RCA derived from concrete cube waste can serve as a substitute for sand in producing lightweight interlock blocks.Keywords: construction waste, recycled aggregates (RCA), sustainable concrete, structure material
Procedia PDF Downloads 52940 Acrylate-Based Photopolymer Resin Combined with Acrylated Epoxidized Soybean Oil for 3D-Printing
Authors: Raphael Palucci Rosa, Giuseppe Rosace
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Stereolithography (SLA) is one of the 3D-printing technologies that has been steadily growing in popularity for both industrial and personal applications due to its versatility, high accuracy, and low cost. Its printing process consists of using a light emitter to solidify photosensitive liquid resins layer-by-layer to produce solid objects. However, the majority of the resins used in SLA are derived from petroleum and characterized by toxicity, stability, and recalcitrance to degradation in natural environments. Aiming to develop an eco-friendly resin, in this work, different combinations of a standard commercial SLA resin (Peopoly UV professional) with a vegetable-based resin were investigated. To reach this goal, different mass concentrations (varying from 10 to 50 wt%) of acrylated epoxidized soybean oil (AESO), a vegetable resin produced from soyabean oil, were mixed with a commercial acrylate-based resin. 1.0 wt% of Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TPO) was used as photo-initiator, and the samples were printed using a Peopoly moai 130. The machine was set to operate at standard configurations when printing commercial resins. After the print was finished, the excess resin was drained off, and the samples were washed in isopropanol and water to remove any non-reacted resin. Finally, the samples were post-cured for 30 min in a UV chamber. FT-IR analysis was used to confirm the UV polymerization of the formulated resin with different AESO/Peopoly ratios. The signals from 1643.7 to 1616, which corresponds to the C=C stretching of the AESO acrylic acids and Peopoly acrylic groups, significantly decreases after the reaction. The signal decrease indicates the consumption of the double bonds during the radical polymerization. Furthermore, the slight change of the C-O-C signal from 1186.1 to 1159.9 decrease of the signals at 809.5 and 983.1, which corresponds to unsaturated double bonds, are both proofs of the successful polymerization. Mechanical analyses showed a decrease of 50.44% on tensile strength when adding 10 wt% of AESO, but it was still in the same range as other commercial resins. The elongation of break increased by 24% with 10 wt% of AESO and swelling analysis showed that samples with a higher concentration of AESO mixed absorbed less water than their counterparts. Furthermore, high-resolution prototypes were printed using both resins, and visual analysis did not show any significant difference between both products. In conclusion, the AESO resin was successful incorporated into a commercial resin without affecting its printability. The bio-based resin showed lower tensile strength than the Peopoly resin due to network loosening, but it was still in the range of other commercial resins. The hybrid resin also showed better flexibility and water resistance than Peopoly resin without affecting its resolution. Finally, the development of new types of SLA resins is essential to provide new sustainable alternatives to the commercial petroleum-based ones.Keywords: 3D-printing, bio-based, resin, soybean, stereolithography
Procedia PDF Downloads 126939 Post-Soviet LULC Analysis of Tbilisi, Batumi and Kutaisi Using of Remote Sensing and Geo Information System
Authors: Lela Gadrani, Mariam Tsitsagi
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Human is a part of the urban landscape and responsible for it. Urbanization of cities includes the longest phase; thus none of the environment ever undergoes such anthropogenic impact as the area of large cities. The post-Soviet period is very interesting in terms of scientific research. The changes that have occurred in the cities since the collapse of the Soviet Union have not yet been analyzed best to our knowledge. In this context, the aim of this paper is to analyze the changes in the land use of the three large cities of Georgia (Tbilisi, Kutaisi, Batumi). Tbilisi as a capital city, Batumi as a port city, and Kutaisi as a former industrial center. Data used during the research process are conventionally divided into satellite and supporting materials. For this purpose, the largest topographic maps (1:10 000) of all three cities were analyzed, Tbilisi General Plans (1896, 1924), Tbilisi and Kutaisi historical maps. The main emphasis was placed on the classification of Landsat images. In this case, we have classified the images LULC (LandUse / LandCover) of all three cities taken in 1987 and 2016 using the supervised and unsupervised methods. All the procedures were performed in the programs: Arc GIS 10.3.1 and ENVI 5.0. In each classification we have singled out the following classes: built-up area, water bodies, agricultural lands, green cover and bare soil, and calculated the areas occupied by them. In order to check the validity of the obtained results, additionally we used the higher resolution images of CORONA and Sentinel. Ultimately we identified the changes that took place in the land use in the post-Soviet period in the above cities. According to the results, a large wave of changes touched Tbilisi and Batumi, though in different periods. It turned out that in the case of Tbilisi, the area of developed territory has increased by 13.9% compared to the 1987 data, which is certainly happening at the expense of agricultural land and green cover, in particular, the area of agricultural lands has decreased by 4.97%; and the green cover by 5.67%. It should be noted that Batumi has obviously overtaken the country's capital in terms of development. With the unaided eye it is clear that in comparison with other regions of Georgia, everything is different in Batumi. In fact, Batumi is an unofficial summer capital of Georgia. Undoubtedly, Batumi’s development is very important both in economic and social terms. However, there is a danger that in the uneven conditions of urban development, we will eventually get a developed center - Batumi, and multiple underdeveloped peripheries around it. Analysis of the changes in the land use is of utmost importance not only for quantitative evaluation of the changes already implemented, but for future modeling and prognosis of urban development. Raster data containing the classes of land use is an integral part of the city's prognostic models.Keywords: analysis, geo information system, remote sensing, LULC
Procedia PDF Downloads 449938 Clinical Validation of C-PDR Methodology for Accurate Non-Invasive Detection of Helicobacter pylori Infection
Authors: Suman Som, Abhijit Maity, Sunil B. Daschakraborty, Sujit Chaudhuri, Manik Pradhan
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Background: Helicobacter pylori is a common and important human pathogen and the primary cause of peptic ulcer disease and gastric cancer. Currently H. pylori infection is detected by both invasive and non-invasive way but the diagnostic accuracy is not up to the mark. Aim: To set up an optimal diagnostic cut-off value of 13C-Urea Breath Test to detect H. pylori infection and evaluate a novel c-PDR methodology to overcome of inconclusive grey zone. Materials and Methods: All 83 subjects first underwent upper-gastrointestinal endoscopy followed by rapid urease test and histopathology and depending on these results; we classified 49 subjects as H. pylori positive and 34 negative. After an overnight, fast patients are taken 4 gm of citric acid in 200 ml water solution and 10 minute after ingestion of the test meal, a baseline exhaled breath sample was collected. Thereafter an oral dose of 75 mg 13C-Urea dissolved in 50 ml water was given and breath samples were collected upto 90 minute for 15 minute intervals and analysed by laser based high precisional cavity enhanced spectroscopy. Results: We studied the excretion kinetics of 13C isotope enrichment (expressed as δDOB13C ‰) of exhaled breath samples and found maximum enrichment around 30 minute of H. pylori positive patients, it is due to the acid mediated stimulated urease enzyme activity and maximum acidification happened within 30 minute but no such significant isotopic enrichment observed for H. pylori negative individuals. Using Receiver Operating Characteristic (ROC) curve an optimal diagnostic cut-off value, δDOB13C ‰ = 3.14 was determined at 30 minute exhibiting 89.16% accuracy. Now to overcome grey zone problem we explore percentage dose of 13C recovered per hour, i.e. 13C-PDR (%/hr) and cumulative percentage dose of 13C recovered, i.e. c-PDR (%) in exhaled breath samples for the present 13C-UBT. We further explored the diagnostic accuracy of 13C-UBT by constructing ROC curve using c-PDR (%) values and an optimal cut-off value was estimated to be c-PDR = 1.47 (%) at 60 minute, exhibiting 100 % diagnostic sensitivity , 100 % specificity and 100 % accuracy of 13C-UBT for detection of H. pylori infection. We also elucidate the gastric emptying process of present 13C-UBT for H. pylori positive patients. The maximal emptying rate found at 36 minute and half empting time of present 13C-UBT was found at 45 minute. Conclusions: The present study exhibiting the importance of c-PDR methodology to overcome of grey zone problem in 13C-UBT for accurate determination of infection without any risk of diagnostic errors and making it sufficiently robust and novel method for an accurate and fast non-invasive diagnosis of H. pylori infection for large scale screening purposes.Keywords: 13C-Urea breath test, c-PDR methodology, grey zone, Helicobacter pylori
Procedia PDF Downloads 300937 Social Inclusion in Higher Institutions: The Plights of Students with Disabilities in Kaduna Polytechnic, Nigeria
Authors: Mairo H. Ipadeola, Catherine James Atteng
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The term social inclusion refers to a process by which those disadvantaged in society can have access to fully participate in education like others. Student with special needs are expected to learn along with their peers within the some educational institutions which provide adequate access for all. There for, the study sort to understand the typical ways in which students with disabilities (SWD) were denied from fully participating as students in Kaduna Polytechnic. In doing this, two (2) objectives and research questions were raised. Firstly, to explore the attitudes of others towards students with disabilities in the institutions and secondly, to ascertain the extent of social participation and physical accessibility for students with disabilities (SWD) while in the institutions. Based on the objectives the paper postulated the research questions: what are the attitudes of management, teachers, and students towards students with special need in Kaduna Polytechnic and to what extent did the students with disabilities experience social participation and physical accessibility within Kaduna Polytechnic school environment? The study area was Kaduna Polytechnic. The study engaged the interview for the data collected which were transcribed and analyzed by thematic coding. The findings were categorized under themes, sub-themes, and codes. The findings revealed that the perception, behavior, and association experiences of students with disabilities within Kaduna Polytechnic were not encouraging. Their experiences were characterized by negative attitudes, feelings of rejection, neglect, and bullying. Data generated on social participation indicated that 71% of the respondents believed that learning, school activities, recreations, and student politics between SWD and the other student were in the direction of low / very low. All the respondents, particularly students with blindness and physical challenges faced difficulty with environmental and physical access above all within the school environment, classroom, walkways and ramps, Also, directions were none existent in most departments with physical access to classrooms, toilets, cafeterias, and school shops absent or very low (71% and 29% of the respondents). The conclusion was that the physical barriers limited the possibilities of social participation of SWD.The paper made some recommendations such as mass public enlightenment on radio and television to change the perception of society about people with disability. Also, the federal, state, and local governments enact building acts for fresh builders and adopted measures and time frames for existing public buildings to be made accessible for people with disabilities. All stakeholders should ensure that the five (5) percent budget set aside by State Universal Basic Education Board (SUBEB) and/or Tertiary Education Trust Fund (TETFUND) for the provision of specialized equipment and facilities for the student with special needs should be used prudently spent and monitored by the board.cm.Keywords: social inclusion, students with disability, social participation, environmental/physical access
Procedia PDF Downloads 53936 Simultaneous Optimization of Design and Maintenance through a Hybrid Process Using Genetic Algorithms
Authors: O. Adjoul, A. Feugier, K. Benfriha, A. Aoussat
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In general, issues related to design and maintenance are considered in an independent manner. However, the decisions made in these two sets influence each other. The design for maintenance is considered an opportunity to optimize the life cycle cost of a product, particularly in the nuclear or aeronautical field, where maintenance expenses represent more than 60% of life cycle costs. The design of large-scale systems starts with product architecture, a choice of components in terms of cost, reliability, weight and other attributes, corresponding to the specifications. On the other hand, the design must take into account maintenance by improving, in particular, real-time monitoring of equipment through the integration of new technologies such as connected sensors and intelligent actuators. We noticed that different approaches used in the Design For Maintenance (DFM) methods are limited to the simultaneous characterization of the reliability and maintainability of a multi-component system. This article proposes a method of DFM that assists designers to propose dynamic maintenance for multi-component industrial systems. The term "dynamic" refers to the ability to integrate available monitoring data to adapt the maintenance decision in real time. The goal is to maximize the availability of the system at a given life cycle cost. This paper presents an approach for simultaneous optimization of the design and maintenance of multi-component systems. Here the design is characterized by four decision variables for each component (reliability level, maintainability level, redundancy level, and level of monitoring data). The maintenance is characterized by two decision variables (the dates of the maintenance stops and the maintenance operations to be performed on the system during these stops). The DFM model helps the designers choose technical solutions for the large-scale industrial products. Large-scale refers to the complex multi-component industrial systems and long life-cycle, such as trains, aircraft, etc. The method is based on a two-level hybrid algorithm for simultaneous optimization of design and maintenance, using genetic algorithms. The first level is to select a design solution for a given system that considers the life cycle cost and the reliability. The second level consists of determining a dynamic and optimal maintenance plan to be deployed for a design solution. This level is based on the Maintenance Free Operating Period (MFOP) concept, which takes into account the decision criteria such as, total reliability, maintenance cost and maintenance time. Depending on the life cycle duration, the desired availability, and the desired business model (sales or rental), this tool provides visibility of overall costs and optimal product architecture.Keywords: availability, design for maintenance (DFM), dynamic maintenance, life cycle cost (LCC), maintenance free operating period (MFOP), simultaneous optimization
Procedia PDF Downloads 116935 Rational Approach to Analysis and Construction of Curved Composite Box Girders in Bridges
Authors: Dongming Feng, Fangyin Zhang, Liling Cao
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Horizontally curved steel-concrete composite box girders are extensively used in highway bridges. They consist of reinforced concrete deck on top of prefabricated steel box section beam which exhibits a high torsional rigidity to resist torsional effects induced by the curved structural geometry. This type of structural system is often constructed in two stages. The composite section will take the tension mainly by the steel box and, the compression by the concrete deck. The steel girders are delivered in large pre-fabricated U-shaped sections that are designed for ease of construction. They are then erected on site and overlaid by cast-in-place reinforced concrete deck. The functionality of the composite section is not achieved until the closed section is formed by fully cured concrete. Since this kind of composite section is built in two stages, the erection of the open steel box presents some challenges to contractors. When the reinforced concrete slab is cast-in-place, special care should be taken on bracings that can prevent the open U-shaped steel box from global and local buckling. In the case of multiple steel boxes, the design detailing should pay enough attention to the installation requirement of the bracings connecting adjacent steel boxes to prevent the global buckling. The slope in transverse direction and grade in longitudinal direction will result in some local deformation of the steel boxes that affect the connection of the bracings. During the design phase, it is common for engineers to model the curved composite box girder using one-dimensional beam elements. This is adequate to analyze the global behavior, however, it is unable to capture the local deformation which affects the installation of the field bracing connection. The presence of the local deformation may become a critical component to control the construction tolerance, and overlooking this deformation will produce inadequate structural details that eventually cause misalignment in field and erection failure. This paper will briefly describe the construction issues we encountered in real structures, investigate the difference between beam element modeling and shell/solid element modeling, and their impact on the different construction stages. P-delta effect due to the slope and curvature of the composite box girder is analyzed, and the secondary deformation is compared to the first-order response and evaluated for its impact on installation of lateral bracings. The paper will discuss the rational approach to prepare construction documents and recommendations are made on the communications between engineers, erectors, and fabricators to smooth out construction process.Keywords: buckling, curved composite box girder, stage construction, structural detailing
Procedia PDF Downloads 120934 Numerical Simulation of the Heat Transfer Process in a Double Pipe Heat Exchanger
Authors: J. I. Corcoles, J. D. Moya-Rico, A. Molina, J. F. Belmonte, J. A. Almendros-Ibanez
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One of the most common heat exchangers technology in engineering processes is the use of double-pipe heat exchangers (DPHx), mainly in the food industry. To improve the heat transfer performance, several passive geometrical devices can be used, such as the wall corrugation of tubes, which increases the wet perimeter maintaining a constant cross-section area, increasing consequently the convective surface area. It contributes to enhance heat transfer in forced convection, promoting secondary recirculating flows. One of the most extended tools to analyse heat exchangers' efficiency is the use of computational fluid dynamic techniques (CFD), a complementary activity to the experimental studies as well as a previous step for the design of heat exchangers. In this study, a double pipe heat exchanger behaviour with two different inner tubes, smooth and spirally corrugated tube, have been analysed. Hence, experimental analysis and steady 3-D numerical simulations using the commercial code ANSYS Workbench v. 17.0 are carried out to analyse the influence of geometrical parameters for spirally corrugated tubes at turbulent flow. To validate the numerical results, an experimental setup has been used. To heat up or cool down the cold fluid as it passes through the heat exchanger, the installation includes heating and cooling loops served by an electric boiler with a heating capacity of 72 kW and a chiller, with a cooling capacity of 48 kW. Two tests have been carried out for the smooth tube and for the corrugated one. In all the tests, the hot fluid has a constant flowrate of 50 l/min and inlet temperature of 59.5°C. For the cold fluid, the flowrate range from 25 l/min (Test 1) and 30 l/min (Test 2) with an inlet temperature of 22.1°C. The heat exchanger is made of stainless steel, with an external diameter of 35 mm and wall thickness of 1.5 mm. Both inner tubes have an external diameter of 24 mm and 1 mm thickness of stainless steel with a length of 2.8 m. The corrugated tube has a corrugation height (H) of 1.1 mm and helical pitch (P) of 25 mm. It is characterized using three non-dimensional parameters, the ratio of the corrugation shape and the diameter (H/D), the helical pitch (P/D) and the severity index (SI = H²/P x D). The results showed good agreement between the numerical and the experimental results. Hence, the lowest differences were shown for the fluid temperatures. In all the analysed tests and for both analysed tubes, the temperature obtained numerically was slightly higher than the experimental results, with values ranged between 0.1% and 0.7%. Regarding the pressure drop, the maximum differences between the values obtained numerically, and the experimental values were close to 16%. Based on the experimental and the numerical results, for the corrugated tube, it can be highlighted that the temperature difference between the inlet and the outlet of the cold fluid is 42%, higher than the smooth tube.Keywords: corrugated tube, heat exchanger, heat transfer, numerical simulation
Procedia PDF Downloads 144933 Nitrate Photoremoval in Water Using Nanocatalysts Based on Ag / Pt over TiO2
Authors: Ana M. Antolín, Sandra Contreras, Francesc Medina, Didier Tichit
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Introduction: High levels of nitrates (> 50 ppm NO3-) in drinking water are potentially risky to human health. In the recent years, the trend of nitrate concentration in groundwater is rising in the EU and other countries. Conventional catalytic nitrate reduction processes into N2 and H2O lead to some toxic intermediates and by-products, such as NO2-, NH4+, and NOx gases. Alternatively, photocatalytic nitrate removal using solar irradiation and heterogeneous catalysts is a very promising and ecofriendly technique. It has been scarcely performed and more research on highly efficient catalysts is still needed. In this work, different nanocatalysts supported on Aeroxide Titania P25 (P25) have been prepared varying: 0.5-4 % wt. Ag); Pt (2, 4 % wt.); Pt precursor (H2PtCl6/K2PtCl6); and impregnation order of both metals. Pt was chosen in order to increase the selectivity to N2 and decrease that to NO2-. Catalysts were characterized by nitrogen physisorption, X-Ray diffraction, UV-visible spectroscopy, TEM and X Ray-Photoelectron Spectroscopy. The aim was to determine the influence of the composition and the preparation method of the catalysts on the conversion and selectivity in the nitrate reduction, as well as going through an overall and better understanding of the process. Nanocatalysts synthesis: For the mono and bimetallic catalysts preparation, wise-drop wetness impregnation of the precursors (AgNO3, H2PtCl6, K2PtCl6) followed by a reduction step (NaBH4) was used to obtain the metal colloids. Results and conclusions: Denitration experiments were performed in a 350 mL PTFE batch reactor under inert standard operational conditions, ultraviolet irradiations (λ=254 nm (UV-C); λ=365 nm (UV-A)), and presence/absence of hydrogen gas as a reducing agent, contrary to most studies using oxalic or formic acid. Samples were analyzed by Ionic Chromatography. Blank experiments using respectively P25 (dark conditions), hydrogen only and UV irradiations without hydrogen demonstrated a clear influence of the presence of hydrogen on nitrate reduction. Also, they demonstrated that UV irradiation increased the selectivity to N2. Interestingly, the best activity was obtained under ultraviolet lamps, especially at a closer wavelength to visible light irradiation (λ = 365 nm) and H2. 2% Ag/P25 leaded to the highest NO3- conversion among the monometallic catalysts. However, nitrite quantities have to be diminished. On the other hand, practically no nitrate conversion was observed with the monometallics based on Pt/P25. Therefore, the amount of 2% Ag was chosen for the bimetallic catalysts. Regarding the bimetallic catalysts, it is observed that the metal impregnation order, amount and Pt precursor highly affects the results. Higher selectivity to the desirable N2 gas is obtained when Pt was firstly added, especially with K2PtCl6 as Pt precursor. This suggests that when Pt is secondly added, it covers the Ag particles, which are the most active in this reaction. It could be concluded that Ag allows the nitrate reduction step to nitrite, and Pt the nitrite reduction step toward the desirable N2 gas.Keywords: heterogeneous catalysis, hydrogenation, nanocatalyst, nitrate removal, photocatalysis
Procedia PDF Downloads 272932 An Integrated Approach to Handle Sour Gas Transportation Problems and Pipeline Failures
Authors: Venkata Madhusudana Rao Kapavarapu
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The Intermediate Slug Catcher (ISC) facility was built to process nominally 234 MSCFD of export gas from the booster station on a day-to-day basis and to receive liquid slugs up to 1600 m³ (10,000 BBLS) in volume when the incoming 24” gas pipelines are pigged following upsets or production of non-dew-pointed gas from gathering centers. The maximum slug sizes expected are 812 m³ (5100 BBLS) in winter and 542 m³ (3400 BBLS) in summer after operating for a month or more at 100 MMSCFD of wet gas, being 60 MMSCFD of treated gas from the booster station, combined with 40 MMSCFD of untreated gas from gathering center. The water content is approximately 60% but may be higher if the line is not pigged for an extended period, owing to the relative volatility of the condensate compared to water. In addition to its primary function as a slug catcher, the ISC facility will receive pigged liquids from the upstream and downstream segments of the 14” condensate pipeline, returned liquids from the AGRP, pigged through the 8” pipeline, and blown-down fluids from the 14” condensate pipeline prior to maintenance. These fluids will be received in the condensate flash vessel or the condensate separator, depending on the specific operation, for the separation of water and condensate and settlement of solids scraped from the pipelines. Condensate meeting the colour and 200 ppm water specifications will be dispatched to the AGRP through the 14” pipeline, while off-spec material will be returned to BS-171 via the existing 10” condensate pipeline. When they are not in operation, the existing 24” export gas pipeline and the 10” condensate pipeline will be maintained under export gas pressure, ready for operation. The gas manifold area contains the interconnecting piping and valves needed to align the slug catcher with either of the 24” export gas pipelines from the booster station and to direct the gas to the downstream segment of either of these pipelines. The manifold enables the slug catcher to be bypassed if it needs to be maintained or if through-pigging of the gas pipelines is to be performed. All gas, whether bypassing the slug catcher or returning to the gas pipelines from it, passes through black powder filters to reduce the level of particulates in the stream. These items are connected to the closed drain vessel to drain the liquid collected. Condensate from the booster station is transported to AGRP through 14” condensate pipeline. The existing 10” condensate pipeline will be used as a standby and for utility functions such as returning condensate from AGRP to the ISC or booster station or for transporting off-spec fluids from the ISC back to booster station. The manifold contains block valves that allow the two condensate export lines to be segmented at the ISC, thus facilitating bi-directional flow independently in the upstream and downstream segments, which ensures complete pipeline integrity and facility integrity. Pipeline failures will be attended to with the latest technologies by remote techno plug techniques, and repair activities will be carried out as needed. Pipeline integrity will be evaluated with ili pigging to estimate the pipeline conditions.Keywords: integrity, oil & gas, innovation, new technology
Procedia PDF Downloads 70931 Sociology Perspective on Emotional Maltreatment: Retrospective Case Study in a Japanese Elementary School
Authors: Nozomi Fujisaka
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This sociological case study analyzes a sequence of student maltreatment in an elementary school in Japan, based on narratives from former students. Among various forms of student maltreatment, emotional maltreatment has received less attention. One reason for this is that emotional maltreatment is often considered part of education and is difficult to capture in surveys. To discuss the challenge of recognizing emotional maltreatment, it's necessary to consider the social background in which student maltreatment occurs. Therefore, from the perspective of the sociology of education, this study aims to clarify the process through which emotional maltreatment was embraced by students within a Japanese classroom. The focus of this study is a series of educational interactions by a homeroom teacher with 11- or 12-year-old students at a small public elementary school approximately 10 years ago. The research employs retrospective narrative data collected through interviews and autoethnography. The semi-structured interviews, lasting one to three hours each, were conducted with 11 young people who were enrolled in the same class as the researcher during their time in elementary school. Autoethnography, as a critical research method, contributes to existing theories and studies by providing a critical representation of the researcher's own experiences. Autoethnography enables researchers to collect detailed data that is often difficult to verbalize in interviews. These research methods are well-suited for this study, which aims to shift the focus from teachers' educational intentions to students' perspectives and gain a deeper understanding of student maltreatment. The research results imply a pattern of emotional maltreatment that is challenging to differentiate from education. In this study's case, the teacher displayed calm and kind behavior toward students after a threat and an explosion of anger. Former students frequently mentioned this behavior of the teacher and perceived emotional maltreatment as part of education. It was not uncommon for former students to offer positive evaluations of the teacher despite experiencing emotional distress. These findings are analyzed and discussed in conjunction with the deschooling theory and the cycle of violence theory. The deschooling theory provides a sociological explanation for how emotional maltreatment can be overlooked in society. The cycle of violence theory, originally developed within the context of domestic violence, explains how violence between romantic partners can be tolerated due to prevailing social norms. Analyzing the case in association with these two theories highlights the characteristics of teachers' behaviors that rationalize maltreatment as education and hinder students from escaping emotional maltreatment. This study deepens our understanding of the causes of student maltreatment and provides a new perspective for future qualitative and quantitative research. Furthermore, since this research is based on the sociology of education, it has the potential to expand research in the fields of pedagogy and sociology, in addition to psychology and social welfare.Keywords: emotional maltreatment, education, student maltreatment, Japan
Procedia PDF Downloads 84930 Analyzing the Participation of Young People in Politics: An Exploratory Study Applied on Motivation in Croatia
Authors: Valentina Piric, Maja Martinovic, Zoran Barac
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The application of marketing to the domain of politics has become relevant in recent times. With this article the authors wanted to explore the issue of the current political engagement among young people in Croatia. The question is what makes young people (age 18-30) politically active in young democracies such as that of the Republic of Croatia. Therefore, the objective of this study was to discover the real or hidden motivations behind the decision to actively participate in politics among young members of the two largest political parties in the country – the Croatian Democratic Union and the Social Democratic Party of Croatia. The study expected to find that the motivation for political engagement of young people is often connected with a possible achievement of individual goals and egoistic needs such as: self-acceptance, social success, financial success, prestige, reputation, status, recognition from the others etc. It was also expected that, due to the poor economic and social situation in the country, young people feel an increasing disconnection from politics. Additionally, the authors expected to find that there is a huge potential to engage young people in the political life of the country through a proper and more interactive use of marketing communication campaigns and social media platforms, with an emphasis on highly ethical motives of political activity and their benefits to society. All respondents included in the quantitative survey (sample size [N=100]) are active in one of the two largest political parties in Croatia. The sampling and distribution of the survey occurred in the field in September 2016. The results of the survey demonstrate that in Croatia, the way young people feel about politics and act accordingly, are in fact similar to what the theory describes. The research findings reveal that young people are politically active; however, the challenge is to find a way to motivate even more young people in Croatia to actively participate in the political and democratic processes in the country and to encourage them to see additional benefits out of this practice, not only related to their individual motives, but related more to the well-being of Croatia as a country and of every member of society. The research also discovered a huge potential for political marketing communication possibilities, especially related to interactive social media. It is possible that the social media channels have a stronger influence on the decision-making process among young people when compared to groups of reference. The level of interest in politics among young Croatians varies; some of them are almost indifferent, whilst others express a serious interest in different ways to actively contribute to the political life of the country, defining a participation in the political life of their country almost as their moral obligation. However, additional observations and further research need to be conducted to get a clearer and more precise picture about the interest in politics among young people in Croatia and their social potential.Keywords: Croatia, marketing communication, motivation, politics, young people
Procedia PDF Downloads 332929 Correlation between Body Mass Dynamics and Weaning in Eurasian Lynx (Lynx lynx L, 1758)
Authors: A. S. Fetisova, M. N. Erofeeva, G. S. Alekseeva, K. A. Volobueva, M. D. Kim, S. V. Naidenko
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Weaning is characterized by the transition from milk to solid food. In some species, such changes in diet are fast and gradual in others. The reasons for the weaning start are understandable. Changes in milk composition and decrease in maternity behavior push cubs to search for additional sources of nutrients. In nature, females have many opportunities to wean offspring in case of a lack of resources. In contrast, in controlled conditions the possibility of delayed weaning exists. The delay of weaning can lead to overspending of maternal resources. In addition, the main causes of weaning end are not so obvious. Near the weaning end behavior of offspring depends on many factors: intensity of maternal behavior, reduction of milk abundance, brood size, physiological status, and body mass. During the pre-weaning period dynamic of body mass is strongly connected with milk intake. Based on that fact could body mass be one of the signals for end of milk feeding? It is known that some animals usually wean their offspring when juveniles achieved body mass in some proportion to the adult weight. In turn, we put forward the hypothesis that decrease in growth rates causes the delay of weaning in Eurasian lynxes (Lynx lynx). To explore the hypothesis, we compared the dynamic of body mass with duration of milk suckling. Firstly, to get information about duration of suckling we visually observed 8 lynx broods from 30 to 120 days postpartum. During each 4-hour observation we registered the start and the end of suckling acts and then calculate the total duration of this behavior. To get the dynamic of body mass kittens were weighed once a week. Duration of suckling varied from 3076,19 ± 1408,60 to 422,54 ± 285,38 seconds when body mass gain changed from 247,35 ± 26,49 to 289,41 ± 122,35 grams. Results of Kendall Tau correlation test (N= 96; p< 0,05) showed a negative correlation (τ= -0,36) between duration of suckling and body mass of lynx kittens. In general duration of suckling increases in response to decrease in body mass gain with slight delay. In early weaning from 30 to 58 days duration of suckling decreases gradually as does the body mass gain. During the weaning period the negative correlation between suckling time and body mass becomes tighter. Although throughout the weaning consumption of solid food begins to prevail over the milk intake, the correlation persists until the end of weaning (90-105 days) and after it. In that way weaning in Eurasian lynxes is not a part of ontogenesis controlled only by maternal behavior. It seems to be a flexible process influenced by various factors including changes in growth rates. It is necessary to continue investigations to determine the critical value of body mass which marks the safe moment to stop milk feeding. Understanding such details of ontogenesis is very important to organize procedures aimed at the reproduction of mammals ex situ and the conservation of endangered species.Keywords: body mass, lynx, milk feeding, weaning
Procedia PDF Downloads 17928 Influence of a Cationic Membrane in a Double Compartment Filter-Press Reactor on the Atenolol Electro-Oxidation
Authors: Alan N. A. Heberle, Salatiel W. Da Silva, Valentin Perez-Herranz, Andrea M. Bernardes
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Contaminants of emerging concern are substances widely used, such as pharmaceutical products. These compounds represent risk for both wild and human life since they are not completely removed from wastewater by conventional wastewater treatment plants. In the environment, they can be harm even in low concentration (µ or ng/L), causing bacterial resistance, endocrine disruption, cancer, among other harmful effects. One of the most common taken medicine to treat cardiocirculatory diseases is the Atenolol (ATL), a β-Blocker, which is toxic to aquatic life. In this way, it is necessary to implement a methodology, which is capable to promote the degradation of the ATL, to avoid the environmental detriment. A very promising technology is the advanced electrochemical oxidation (AEO), which mechanisms are based on the electrogeneration of reactive radicals (mediated oxidation) and/or on the direct substance discharge by electron transfer from contaminant to electrode surface (direct oxidation). The hydroxyl (HO•) and sulfate (SO₄•⁻) radicals can be generated, depending on the reactional medium. Besides that, at some condition, the peroxydisulfate (S₂O₈²⁻) ion is also generated from the SO₄• reaction in pairs. Both radicals, ion, and the direct contaminant discharge can break down the molecule, resulting in the degradation and/or mineralization. However, ATL molecule and byproducts can still remain in the treated solution. On this wise, some efforts can be done to implement the AEO process, being one of them the use of a cationic membrane to separate the cathodic (reduction) from the anodic (oxidation) reactor compartment. The aim of this study is investigate the influence of the implementation of a cationic membrane (Nafion®-117) to separate both cathodic and anodic, AEO reactor compartments. The studied reactor was a filter-press, with bath recirculation mode, flow 60 L/h. The anode was an Nb/BDD2500 and the cathode a stainless steel, both bidimensional, geometric surface area 100 cm². The solution feeding the anodic compartment was prepared with ATL 100 mg/L using Na₂SO₄ 4 g/L as support electrolyte. In the cathodic compartment, it was used a solution containing Na₂SO₄ 71 g/L. Between both solutions was placed the membrane. The applied currents densities (iₐₚₚ) of 5, 20 and 40 mA/cm² were studied over 240 minutes treatment time. Besides that, the ATL decay was analyzed by ultraviolet spectroscopy (UV/Vis). The mineralization was determined performing total organic carbon (TOC) in TOC-L CPH Shimadzu. In the cases without membrane, the iₐₚₚ 5, 20 and 40 mA/cm² resulted in 55, 87 and 98 % ATL degradation at the end of treatment time, respectively. However, with membrane, the degradation, for the same iₐₚₚ, was 90, 100 and 100 %, spending 240, 120, 40 min for the maximum degradation, respectively. The mineralization, without membrane, for the same studied iₐₚₚ, was 40, 55 and 72 %, respectively at 240 min, but with membrane, all tested iₐₚₚ reached 80 % of mineralization, differing only in the time spent, 240, 150 and 120 min, for the maximum mineralization, respectively. The membrane increased the ATL oxidation, probably due to avoid oxidant ions (S₂O₈²⁻) reduction on the cathode surface.Keywords: contaminants of emerging concern, advanced electrochemical oxidation, atenolol, cationic membrane, double compartment reactor
Procedia PDF Downloads 135927 A Bayesian Approach for Health Workforce Planning in Portugal
Authors: Diana F. Lopes, Jorge Simoes, José Martins, Eduardo Castro
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Health professionals are the keystone of any health system, by delivering health services to the population. Given the time and cost involved in training new health professionals, the planning process of the health workforce is particularly important as it ensures a proper balance between the supply and demand of these professionals and it plays a central role on the Health 2020 policy. In the past 40 years, the planning of the health workforce in Portugal has been conducted in a reactive way lacking a prospective vision based on an integrated, comprehensive and valid analysis. This situation may compromise not only the productivity and the overall socio-economic development but the quality of the healthcare services delivered to patients. This is even more critical given the expected shortage of the health workforce in the future. Furthermore, Portugal is facing an aging context of some professional classes (physicians and nurses). In 2015, 54% of physicians in Portugal were over 50 years old, and 30% of all members were over 60 years old. This phenomenon associated to an increasing emigration of young health professionals and a change in the citizens’ illness profiles and expectations must be considered when planning resources in healthcare. The perspective of sudden retirement of large groups of professionals in a short time is also a major problem to address. Another challenge to embrace is the health workforce imbalances, in which Portugal has one of the lowest nurse to physician ratio, 1.5, below the European Region and the OECD averages (2.2 and 2.8, respectively). Within the scope of the HEALTH 2040 project – which aims to estimate the ‘Future needs of human health resources in Portugal till 2040’ – the present study intends to get a comprehensive dynamic approach of the problem, by (i) estimating the needs of physicians and nurses in Portugal, by specialties and by quinquenium till 2040; (ii) identifying the training needs of physicians and nurses, in medium and long term, till 2040, and (iii) estimating the number of students that must be admitted into medicine and nursing training systems, each year, considering the different categories of specialties. The development of such approach is significantly more critical in the context of limited budget resources and changing health care needs. In this context, this study presents the drivers of the healthcare needs’ evolution (such as the demographic and technological evolution, the future expectations of the users of the health systems) and it proposes a Bayesian methodology, combining the best available data with experts opinion, to model such evolution. Preliminary results considering different plausible scenarios are presented. The proposed methodology will be integrated in a user-friendly decision support system so it can be used by politicians, with the potential to measure the impact of health policies, both at the regional and the national level.Keywords: bayesian estimation, health economics, health workforce planning, human health resources planning
Procedia PDF Downloads 251926 Option Pricing Theory Applied to the Service Sector
Authors: Luke Miller
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This paper develops an options pricing methodology to value strategic pricing strategies in the services sector. More specifically, this study provides a unifying taxonomy of current service sector pricing practices, frames these pricing decisions as strategic real options, demonstrates accepted option valuation techniques to assess service sector pricing decisions, and suggests future research areas where pricing decisions and real options overlap. Enhancing revenue in the service sector requires proactive decision making in a world of uncertainty. In an effort to strategically price service products, revenue enhancement necessitates a careful study of the service costs, customer base, competition, legalities, and shared economies with the market. Pricing decisions involve the quality of inputs, manpower, and best practices to maintain superior service. These decisions further hinge on identifying relevant pricing strategies and understanding how these strategies impact a firm’s value. A relatively new area of research applies option pricing theory to investments in real assets and is commonly known as real options. The real options approach is based on the premise that many corporate decisions to invest or divest in assets are simply an option wherein the firm has the right to make an investment without any obligation to act. The decision maker, therefore, has more flexibility and the value of this operating flexibility should be taken into consideration. The real options framework has already been applied to numerous areas including manufacturing, inventory, natural resources, research and development, strategic decisions, technology, and stock valuation. Additionally, numerous surveys have identified a growing need for the real options decision framework within all areas of corporate decision-making. Despite the wide applicability of real options, no study has been carried out linking service sector pricing decisions and real options. This is surprising given the service sector comprises 80% of the US employment and Gross Domestic Product (GDP). Identifying real options as a practical tool to value different service sector pricing strategies is believed to have a significant impact on firm decisions. This paper identifies and discusses four distinct pricing strategies available to the service sector from an options’ perspective: (1) Cost-based profit margin, (2) Increased customer base, (3) Platform pricing, and (4) Buffet pricing. Within each strategy lie several pricing tactics available to the service firm. These tactics can be viewed as options the decision maker has to best manage a strategic position in the market. To demonstrate the effectiveness of including flexibility in the pricing decision, a series of pricing strategies were developed and valued using a real options binomial lattice structure. The options pricing approach discussed in this study allows service firms to directly incorporate market-driven perspectives into the decision process and thus synchronizing service operations with organizational economic goals.Keywords: option pricing theory, real options, service sector, valuation
Procedia PDF Downloads 354925 The Effect of Elapsed Time on the Cardiac Troponin-T Degradation and Its Utility as a Time Since Death Marker in Cases of Death Due to Burn
Authors: Sachil Kumar, Anoop K.Verma, Uma Shankar Singh
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It’s extremely important to study postmortem interval in different causes of death since it assists in a great way in making an opinion on the exact cause of death following such incident often times. With diligent knowledge of the interval one could really say as an expert that the cause of death is not feigned hence there is a great need in evaluating such death to have been at the CRIME SCENE before performing an autopsy on such body. The approach described here is based on analyzing the degradation or proteolysis of a cardiac protein in cases of deaths due to burn as a marker of time since death. Cardiac tissue samples were collected from (n=6) medico-legal autopsies, (Department of Forensic Medicine and Toxicology), King George’s Medical University, Lucknow India, after informed consent from the relatives and studied post-mortem degradation by incubation of the cardiac tissue at room temperature (20±2 OC) for different time periods (~7.30, 18.20, 30.30, 41.20, 41.40, 54.30, 65.20, and 88.40 Hours). The cases included were the subjects of burn without any prior history of disease who died in the hospital and their exact time of death was known. The analysis involved extraction of the protein, separation by denaturing gel electrophoresis (SDS-PAGE) and visualization by Western blot using cTnT specific monoclonal antibodies. The area of the bands within a lane was quantified by scanning and digitizing the image using Gel Doc. As time postmortem progresses the intact cTnT band degrades to fragments that are easily detected by the monoclonal antibodies. A decreasing trend in the level of cTnT (% of intact) was found as the PM hours increased. A significant difference was observed between <15 h and other PM hours (p<0.01). Significant difference in cTnT level (% of intact) was also observed between 16-25 h and 56-65 h & >75 h (p<0.01). Western blot data clearly showed the intact protein at 42 kDa, three major (28 kDa, 30kDa, 10kDa) fragments, three additional minor fragments (12 kDa, 14kDa, and 15 kDa) and formation of low molecular weight fragments. Overall, both PMI and cardiac tissue of burned corpse had a statistically significant effect where the greatest amount of protein breakdown was observed within the first 41.40 Hrs and after it intact protein slowly disappears. If the percent intact cTnT is calculated from the total area integrated within a Western blot lane, then the percent intact cTnT shows a pseudo-first order relationship when plotted against the time postmortem. A strong significant positive correlation was found between cTnT and PM hours (r=0.87, p=0.0001). The regression analysis showed a good variability explained (R2=0.768) The post-mortem Troponin-T fragmentation observed in this study reveals a sequential, time-dependent process with the potential for use as a predictor of PMI in cases of burning.Keywords: burn, degradation, postmortem interval, troponin-T
Procedia PDF Downloads 448924 Mapping and Mitigation Strategy for Flash Flood Hazards: A Case Study of Bishoftu City
Authors: Berhanu Keno Terfa
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Flash floods are among the most dangerous natural disasters that pose a significant threat to human existence. They occur frequently and can cause extensive damage to homes, infrastructure, and ecosystems while also claiming lives. Although flash floods can happen anywhere in the world, their impact is particularly severe in developing countries due to limited financial resources, inadequate drainage systems, substandard housing options, lack of early warning systems, and insufficient preparedness. To address these challenges, a comprehensive study has been undertaken to analyze and map flood inundation using Geographic Information System (GIS) techniques by considering various factors that contribute to flash flood resilience and developing effective mitigation strategies. Key factors considered in the analysis include slope, drainage density, elevation, Curve Number, rainfall patterns, land-use/cover classes, and soil data. These variables were computed using ArcGIS software platforms, and data from the Sentinel-2 satellite image (with a 10-meter resolution) were utilized for land-use/cover classification. Additionally, slope, elevation, and drainage density data were generated from the 12.5-meter resolution of the ALOS Palsar DEM, while other relevant data were obtained from the Ethiopian Meteorological Institute. By integrating and regularizing the collected data through GIS and employing the analytic hierarchy process (AHP) technique, the study successfully delineated flash flood hazard zones (FFHs) and generated a suitable land map for urban agriculture. The FFH model identified four levels of risk in Bishoftu City: very high (2106.4 ha), high (10464.4 ha), moderate (1444.44 ha), and low (0.52 ha), accounting for 15.02%, 74.7%, 10.1%, and 0.004% of the total area, respectively. The results underscore the vulnerability of many residential areas in Bishoftu City, particularly the central areas that have been previously developed. Accurate spatial representation of flood-prone areas and potential agricultural zones is crucial for designing effective flood mitigation and agricultural production plans. The findings of this study emphasize the importance of flood risk mapping in raising public awareness, demonstrating vulnerability, strengthening financial resilience, protecting the environment, and informing policy decisions. Given the susceptibility of Bishoftu City to flash floods, it is recommended that the municipality prioritize urban agriculture adaptation, proper settlement planning, and drainage network design.Keywords: remote sensing, flush flood hazards, Bishoftu, GIS.
Procedia PDF Downloads 34923 Stability of a Biofilm Reactor Able to Degrade a Mixture of the Organochlorine Herbicides Atrazine, Simazine, Diuron and 2,4-Dichlorophenoxyacetic Acid to Changes in the Composition of the Supply Medium
Authors: I. Nava-Arenas, N. Ruiz-Ordaz, C. J. Galindez-Mayer, M. L. Luna-Guido, S. L. Ruiz-López, A. Cabrera-Orozco, D. Nava-Arenas
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Among the most important herbicides, the organochlorine compounds are of considerable interest due to their recalcitrance to the chemical, biological, and photolytic degradation, their persistence in the environment, their mobility, and their bioacummulation. The most widely used herbicides in North America are primarily 2,4-dichlorophenoxyacetic acid (2,4-D), the triazines (atrazine and simazine), and to a lesser extent diuron. The contamination of soils and water bodies frequently occurs by mixtures of these xenobiotics. For this reason, in this work, the operational stability to changes in the composition of the medium supplied to an aerobic biofilm reactor was studied. The reactor was packed with fragments of volcanic rock that retained a complex microbial film, able to degrade a mixture of organochlorine herbicides atrazine, simazine, diuron and 2,4-D, and whose members have microbial genes encoding the main catabolic enzymes atzABCD, tfdACD and puhB. To acclimate the attached microbial community, the biofilm reactor was fed continuously with a mineral minimal medium containing the herbicides (in mg•L-1): diuron, 20.4; atrazine, 14.2, simazine, 11.4, and 2,4-D, 59.7, as carbon and nitrogen sources. Throughout the bioprocess, removal efficiencies of 92-100% for herbicides, 78-90% for COD, 92-96% for TOC and 61-83% for dehalogenation were reached. In the microbial community, the genes encoding catabolic enzymes of different herbicides tfdACD, puhB and, occasionally, the genes atzA and atzC were detected. After the acclimatization, the triazine herbicides were eliminated from the mixture formulation. Volumetric loading rates of the mixture 2,4-D and diuron were continuously supplied to the reactor (1.9-21.5 mg herbicides •L-1 •h-1). Along the bioprocess, the removal efficiencies obtained were 86-100% for the mixture of herbicides, 63-94% for for COD, 90-100% for COT, and dehalogenation values of 63-100%. It was also observed that the genes encoding the enzymes in the catabolism of both herbicides, tfdACD and puhB, were consistently detected; and, occasionally, the atzA and atzC. Subsequently, the triazine herbicide atrazine and simazine were restored to the medium supply. Different volumetric charges of this mixture were continuously fed to the reactor (2.9 to 12.6 mg herbicides •L-1 •h-1). During this new treatment process, removal efficiencies of 65-95% for the mixture of herbicides, 63-92% for COD, 66-89% for TOC and 73-94% of dehalogenation were observed. In this last case, the genes tfdACD, puhB and atzABC encoding for the enzymes involved in the catabolism of the distinct herbicides were consistently detected. The atzD gene, encoding the cyanuric hydrolase enzyme, could not be detected, though it was determined that there was partial degradation of cyanuric acid. In general, the community in the biofilm reactor showed some catabolic stability, adapting to changes in loading rates and composition of the mixture of herbicides, and preserving their ability to degrade the four herbicides tested; although, there was a significant delay in the response time to recover to degradation of the herbicides.Keywords: biodegradation, biofilm reactor, microbial community, organochlorine herbicides
Procedia PDF Downloads 435922 Roads and Agriculture: Impacts of Connectivity in Peru
Authors: Julio Aguirre, Yohnny Campana, Elmer Guerrero, Daniel De La Torre Ugarte
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A well-developed transportation network is a necessary condition for a country to derive full benefits from good trade and macroeconomic policies. Road infrastructure plays a key role in the economic development of rural areas of developing countries; where agriculture is the main economic activity. The ability to move agricultural production from the place of production to the market, and then to the place of consumption, greatly influence the economic value of farming activities, and of the resources involved in the production process, i.e., labor and land. Consequently, investment in transportation networks contributes to enhance or overcome the natural advantages or disadvantages that topography and location have imposed over the agricultural sector. This is of particular importance when dealing with countries, like Peru, with a great topographic diversity. The objective of this research is to estimate the impacts of road infrastructure on the performance of the agricultural sector. Specific variables of interest are changes in travel time, shifts of production for self-consumption to production for the market, changes in farmers income, and impacts on the diversification of the agricultural sector. In the study, a cross-section model with instrumental variables is the central methodological instrument. The data is obtained from agricultural and transport geo-referenced databases, and the instrumental variable specification utilized is based on the Kruskal algorithm. The results show that the expansion of road connectivity reduced farmers' travel time by an average of 3.1 hours and the proportion of output sold in the market increases by up to 40 percentage points. The increase in connectivity has an unexpected increase in the districts index of diversification of agricultural production. The results are robust to the inclusion of year and region fixed-effects, and to control for geography (i.e., slope and altitude), population variables, and mining activity. Other results are also very eloquent. For example, a clear positive impact can be seen in access to local markets, but this does not necessarily correlate with an increase in the production of the sector. This can be explained by the fact that agricultural development not only requires provision of roads but additional complementary infrastructure and investments intended to provide the necessary conditions so that producers can offer quality products (improved management practices, timely maintenance of irrigation infrastructure, transparent management of water rights, among other factors). Therefore, complementary public goods are needed to enhance the effects of roads on the welfare of the population, beyond enabling them to increase their access to markets.Keywords: agriculture devolepment, market access, road connectivity, regional development
Procedia PDF Downloads 205921 Development of an Automatic Computational Machine Learning Pipeline to Process Confocal Fluorescence Images for Virtual Cell Generation
Authors: Miguel Contreras, David Long, Will Bachman
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Background: Microscopy plays a central role in cell and developmental biology. In particular, fluorescence microscopy can be used to visualize specific cellular components and subsequently quantify their morphology through development of virtual-cell models for study of effects of mechanical forces on cells. However, there are challenges with these imaging experiments, which can make it difficult to quantify cell morphology: inconsistent results, time-consuming and potentially costly protocols, and limitation on number of labels due to spectral overlap. To address these challenges, the objective of this project is to develop an automatic computational machine learning pipeline to predict cellular components morphology for virtual-cell generation based on fluorescence cell membrane confocal z-stacks. Methods: Registered confocal z-stacks of nuclei and cell membrane of endothelial cells, consisting of 20 images each, were obtained from fluorescence confocal microscopy and normalized through software pipeline for each image to have a mean pixel intensity value of 0.5. An open source machine learning algorithm, originally developed to predict fluorescence labels on unlabeled transmitted light microscopy cell images, was trained using this set of normalized z-stacks on a single CPU machine. Through transfer learning, the algorithm used knowledge acquired from its previous training sessions to learn the new task. Once trained, the algorithm was used to predict morphology of nuclei using normalized cell membrane fluorescence images as input. Predictions were compared to the ground truth fluorescence nuclei images. Results: After one week of training, using one cell membrane z-stack (20 images) and corresponding nuclei label, results showed qualitatively good predictions on training set. The algorithm was able to accurately predict nuclei locations as well as shape when fed only fluorescence membrane images. Similar training sessions with improved membrane image quality, including clear lining and shape of the membrane, clearly showing the boundaries of each cell, proportionally improved nuclei predictions, reducing errors relative to ground truth. Discussion: These results show the potential of pre-trained machine learning algorithms to predict cell morphology using relatively small amounts of data and training time, eliminating the need of using multiple labels in immunofluorescence experiments. With further training, the algorithm is expected to predict different labels (e.g., focal-adhesion sites, cytoskeleton), which can be added to the automatic machine learning pipeline for direct input into Principal Component Analysis (PCA) for generation of virtual-cell mechanical models.Keywords: cell morphology prediction, computational machine learning, fluorescence microscopy, virtual-cell models
Procedia PDF Downloads 203920 The Valuable Triad of Adipokine Indices to Differentiate Pediatric Obesity from Metabolic Syndrome: Chemerin, Progranulin, Vaspin
Authors: Mustafa M. Donma, Orkide Donma
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Obesity is associated with cardiovascular disease risk factors and metabolic syndrome (MetS). In this study, associations between adipokines and adipokine as well as obesity indices were evaluated. Plasma adipokine levels may exhibit variations according to body adipose tissue mass. Besides, upon consideration of obesity as an inflammatory disease, adipokines may play some roles in this process. The ratios of proinflammatory adipokines to adiponectin may act as highly sensitive indicators of body adipokine status. The aim of the study is to present some adipokine indices, which are thought to be helpful for the evaluation of childhood obesity and also to determine the best discriminators in the diagnosis of MetS. 80 prepubertal children (aged between 6-9.5 years) included in the study were divided into three groups; 30 children with normal weight (NW), 25 morbid obese (MO) children and 25 MO children with MetS. Physical examinations were performed. Written informed consent forms were obtained from the parents. The study protocol was approved by Ethics Committee of Namik Kemal University Medical Faculty. Anthropometric measurements, such as weight, height, waist circumference (C), hip C, head C, neck C were recorded. Values for body mass index (BMI), diagnostic obesity notation model assessment Index-II (D2 index) as well as waist-to-hip, head-to-neck ratios were calculated. Adiponectin, resistin, leptin, chemerin, vaspin, progranulin assays were performed by ELISA. Adipokine-to-adiponectin ratios were obtained. SPSS Version 20 was used for the evaluation of data. p values ≤ 0.05 were accepted as statistically significant. Values of BMI and D2 index, waist-to-hip, head-to-neck ratios did not differ between MO and MetS groups (p ≥ 0.05). Except progranulin (p ≤ 0.01), similar patterns were observed for plasma levels of each adipokine. There was not any difference in vaspin as well as resistin levels between NW and MO groups. Significantly increased leptin-to-adiponectin, chemerin-to-adiponectin and vaspin-to-adiponectin values were noted in MO in comparison with those of NW. The most valuable adipokine index was progranulin-to-adiponectin (p ≤ 0.01). This index was strongly correlated with vaspin-to-adiponectin ratio in all groups (p ≤ 0.05). There was no correlation between vaspin-to-adiponectin and chemerin-to--adiponectin in NW group. However, a correlation existed in MO group (r = 0.486; p ≤ 0.05). Much stronger correlation (r = 0.609; p ≤ 0.01) was observed in MetS group between these two adipokine indices. No correlations were detected between vaspin and progranulin as well as vaspin and chemerin levels. Correlation analyses showed a unique profile confined to MetS children. Adiponectin was found to be correlated with waist-to-hip (r = -0.435; p ≤ 0.05) as well as head-to-neck (r = 0.541; p ≤ 0.05) ratios only in MetS children. In this study, it has been investigated if adipokine indices have priority over adipokine levels. In conclusion, vaspin-to-adiponectin, progranulin-to-adiponectin, chemerin-to-adiponectin along with waist-to-hip and head-to-neck ratios were the optimal combinations. Adiponectin, waist-to-hip, head-to-neck, vaspin-to-adiponectin, chemerin-to-adiponectin ratios had appropriate discriminatory capability for MetS children.Keywords: adipokine indices, metabolic syndrome, obesity indices, pediatric obesity
Procedia PDF Downloads 204919 Using True Life Situations in a Systems Theory Perspective as Sources of Creativity: A Case Study of how to use Everyday Happenings to produce Creative Outcomes in Novel and Screenplay Writing
Authors: Rune Bjerke
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Psychologists incline to see creativity as a mental and psychological process. However, creativity is as well results of cultural and social interactions. Therefore, creativity is not a product of individuals in isolation, but of social systems. Creative people get ideas from the influence of others and the immediate cultural environment – a space of knowledge, situations, and practices. Therefore, in this study we apply the systems theory in practice to activate creativity processes in the production of our novel and screenplay writing. We, as storytellers actively seek to get into situations in our everyday lives, our systems, to generate ideas. Within our personal systems, we have the potential to induce situations to realise ideas to our texts, which may be accepted by our gate-keepers and can become socially validated. This is our method of writing – get into situations, get ideas to texts, and test them with family and friends in our social systems. Example of novel text as an outcome of our method is as follows: “Is it a matter of obviousness or had I read it somewhere, that the one who increases his knowledge increases his pain? And also, the other way around, with increased pain, knowledge increases, I thought. Perhaps such a chain of effects explains why the rebel August Strindberg wrote seven plays in ten months after the divorce with Siri von Essen. Shortly after, he tried painting. Neither the seven theatre plays were shown, nor the paintings were exhibited. I was standing in front of Munch's painting Women in Three Stages with chaotic mental images of myself crumpled in a church and a laughing x-girlfriend watching my suffering. My stomach was turning at unpredictable intervals and the subsequent vomiting almost suffocated me. Love grief at the worst. Was it this pain Strindberg felt? Despite the failure of his first plays, the pain must have triggered a form of creative energy that turned pain into ideas. Suffering, thoughts, feelings, words, text, and then, the reader experience. Maybe this negative force can be transformed into something positive, I asked myself. The question eased my pain. At that moment, I forgot the damp, humid air in the Munch Museum. Is it the similar type of Strindberg-pain that could explain the recurring, depressive themes in Munch's paintings? Illness, death, love and jealousy. As a beginning art student at the master's level, I had decided to find the answer. Was it the same with Munch's pain, as with Strindberg - a woman behind? There had to be women in the case of Munch - therefore, the painting “Women in Three Stages”? Who are they, what personality types are they – the women in red, black and white dresses from left to the right?” We, the writers, are using persons, situations and elements in our systems, in a systems theory perspective, to prompt creative ideas. A conceptual model is provided to advance creativity theory.Keywords: creativity theory, systems theory, novel writing, screenplay writing, sources of creativity in social systems
Procedia PDF Downloads 118918 Synthesis of Methanol through Photocatalytic Conversion of CO₂: A Green Chemistry Approach
Authors: Sankha Chakrabortty, Biswajit Ruj, Parimal Pal
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Methanol is one of the most important chemical products and intermediates. It can be used as a solvent, intermediate or raw material for a number of higher valued products, fuels or additives. From the last one decay, the total global demand of methanol has increased drastically which forces the scientists to produce a large amount of methanol from a renewable source to meet the global demand with a sustainable way. Different types of non-renewable based raw materials have been used for the synthesis of methanol on a large scale which makes the process unsustainable. In this circumstances, photocatalytic conversion of CO₂ into methanol under solar/UV excitation becomes a viable approach to give a sustainable production approach which not only meets the environmental crisis by recycling CO₂ to fuels but also reduces CO₂ amount from the atmosphere. Development of such sustainable production approach for CO₂ conversion into methanol still remains a major challenge in the current research comparing with conventional energy expensive processes. In this backdrop, the development of environmentally friendly materials, like photocatalyst has taken a great perspective for methanol synthesis. Scientists in this field are always concerned about finding an improved photocatalyst to enhance the photocatalytic performance. Graphene-based hybrid and composite materials with improved properties could be a better nanomaterial for the selective conversion of CO₂ to methanol under visible light (solar energy) or UV light. The present invention relates to synthesis an improved heterogeneous graphene-based photocatalyst with improved catalytic activity and surface area. Graphene with enhanced surface area is used as coupled material of copper-loaded titanium oxide to improve the electron capture and transport properties which substantially increase the photoinduced charge transfer and extend the lifetime of photogenerated charge carriers. A fast reduction method through H₂ purging has been adopted to synthesis improved graphene whereas ultrasonication based sol-gel method has been applied for the preparation of graphene coupled copper loaded titanium oxide with some enhanced properties. Prepared photocatalysts were exhaustively characterized using different characterization techniques. Effects of catalyst dose, CO₂ flow rate, reaction temperature and stirring time on the efficacy of the system in terms of methanol yield and productivity have been studied in the present study. The study shown that the newly synthesized photocatalyst with an enhanced surface resulting in a sustained productivity and yield of methanol 0.14 g/Lh, and 0.04 g/gcat respectively, after 3 h of illumination under UV (250W) at an optimum catalyst dosage of 10 g/L having 1:2:3 (Graphene: TiO₂: Cu) weight ratio.Keywords: renewable energy, CO₂ capture, photocatalytic conversion, methanol
Procedia PDF Downloads 107917 Molecular Modeling and Prediction of the Physicochemical Properties of Polyols in Aqueous Solution
Authors: Maria Fontenele, Claude-Gilles Dussap, Vincent Dumouilla, Baptiste Boit
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Roquette Frères is a producer of plant-based ingredients that employs many processes to extract relevant molecules and often transforms them through chemical and physical processes to create desired ingredients with specific functionalities. In this context, Roquette encounters numerous multi-component complex systems in their processes, including fibers, proteins, and carbohydrates, in an aqueous environment. To develop, control, and optimize both new and old processes, Roquette aims to develop new in silico tools. Currently, Roquette uses process modelling tools which include specific thermodynamic models and is willing to develop computational methodologies such as molecular dynamics simulations to gain insights into the complex interactions in such complex media, and especially hydrogen bonding interactions. The issue at hand concerns aqueous mixtures of polyols with high dry matter content. The polyols mannitol and sorbitol molecules are diastereoisomers that have nearly identical chemical structures but very different physicochemical properties: for example, the solubility of sorbitol in water is 2.5 kg/kg of water, while mannitol has a solubility of 0.25 kg/kg of water at 25°C. Therefore, predicting liquid-solid equilibrium properties in this case requires sophisticated solution models that cannot be based solely on chemical group contributions, knowing that for mannitol and sorbitol, the chemical constitutive groups are the same. Recognizing the significance of solvation phenomena in polyols, the GePEB (Chemical Engineering, Applied Thermodynamics, and Biosystems) team at Institut Pascal has developed the COSMO-UCA model, which has the structural advantage of using quantum mechanics tools to predict formation and phase equilibrium properties. In this work, we use molecular dynamics simulations to elucidate the behavior of polyols in aqueous solution. Specifically, we employ simulations to compute essential metrics such as radial distribution functions and hydrogen bond autocorrelation functions. Our findings illuminate a fundamental contrast: sorbitol and mannitol exhibit disparate hydrogen bond lifetimes within aqueous environments. This observation serves as a cornerstone in elucidating the divergent physicochemical properties inherent to each compound, shedding light on the nuanced interplay between their molecular structures and water interactions. We also present a methodology to predict the physicochemical properties of complex solutions, taking as sole input the three-dimensional structure of the molecules in the medium. Finally, by developing knowledge models, we represent some physicochemical properties of aqueous solutions of sorbitol and mannitol.Keywords: COSMO models, hydrogen bond, molecular dynamics, thermodynamics
Procedia PDF Downloads 41916 Evaluation of Groundwater Quality and Contamination Sources Using Geostatistical Methods and GIS in Miryang City, Korea
Authors: H. E. Elzain, S. Y. Chung, V. Senapathi, Kye-Hun Park
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Groundwater is considered a significant source for drinking and irrigation purposes in Miryang city, and it is attributed to a limited number of a surface water reservoirs and high seasonal variations in precipitation. Population growth in addition to the expansion of agricultural land uses and industrial development may affect the quality and management of groundwater. This research utilized multidisciplinary approaches of geostatistics such as multivariate statistics, factor analysis, cluster analysis and kriging technique in order to identify the hydrogeochemical process and characterizing the control factors of the groundwater geochemistry distribution for developing risk maps, exploiting data obtained from chemical investigation of groundwater samples under the area of study. A total of 79 samples have been collected and analyzed using atomic absorption spectrometer (AAS) for major and trace elements. Chemical maps using 2-D spatial Geographic Information System (GIS) of groundwater provided a powerful tool for detecting the possible potential sites of groundwater that involve the threat of contamination. GIS computer based map exhibited that the higher rate of contamination observed in the central and southern area with relatively less extent in the northern and southwestern parts. It could be attributed to the effect of irrigation, residual saline water, municipal sewage and livestock wastes. At wells elevation over than 85m, the scatter diagram represents that the groundwater of the research area was mainly influenced by saline water and NO3. Level of pH measurement revealed low acidic condition due to dissolved atmospheric CO2 in the soil, while the saline water had a major impact on the higher values of TDS and EC. Based on the cluster analysis results, the groundwater has been categorized into three group includes the CaHCO3 type of the fresh water, NaHCO3 type slightly influenced by sea water and Ca-Cl, Na-Cl types which are heavily affected by saline water. The most predominant water type was CaHCO3 in the study area. Contamination sources and chemical characteristics were identified from factor analysis interrelationship and cluster analysis. The chemical elements that belong to factor 1 analysis were related to the effect of sea water while the elements of factor 2 associated with agricultural fertilizers. The degree level, distribution, and location of groundwater contamination have been generated by using Kriging methods. Thus, geostatistics model provided more accurate results for identifying the source of contamination and evaluating the groundwater quality. GIS was also a creative tool to visualize and analyze the issues affecting water quality in the Miryang city.Keywords: groundwater characteristics, GIS chemical maps, factor analysis, cluster analysis, Kriging techniques
Procedia PDF Downloads 167915 Metamorphosis of Caste: An Examination of the Transformation of Caste from a Material to Ideological Phenomenon in Sri Lanka
Authors: Pradeep Peiris, Hasini Lecamwasam
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The fluid, ambiguous, and often elusive existence of caste among the Sinhalese in Sri Lanka has inspired many scholarly endeavours. Originally, Sinhalese caste was organized according to the occupational functions assigned to various groups in society. Hence cultivators came to be known as Goyigama, washers Dobi, drummers Berava, smiths Navandanna and so on. During pre-colonial times the specialized services of various groups were deployed to build water reservoirs, cultivate the land, and/or sustain the Buddhist order by material means. However, as to how and why caste prevails today in Sinhalese society when labour is in ideal terms free to move where it wants, or in other words, occupation is no longer strictly determined or restricted by birth, is a question worth exploring. Hence this paper explores how, and perhaps more interestingly why, when the nexus between traditional occupations and caste status is fast disappearing, caste itself has managed to survive and continues to be salient in politics in Sri Lanka. In answer to this larger question, the paper looks at caste from three perspectives: 1) Buddhism, whose ethical project provides a justification of social stratifications that transcends economic bases 2) Capitalism that has reactivated and reproduced archaic relations in a process of 'accumulation by subordination', not only by reinforcing the marginality of peripheral caste groups, but also by exploiting caste divisions to hinder any realization of class interests and 3) Democracy whose supposed equalizing effect expected through its ‘one man–one vote’ approach has been subverted precisely by itself, whereby the aggregate ultimately comes down to how many such votes each ‘group’ in society has. This study draws from field work carried out in Dedigama (in the District of Kegalle, Central Province) and Kelaniya (in the District of Colombo, Western Province) in Sri Lanka over three years. The choice of field locations was encouraged by the need to capture rural and urban dynamics related to caste since caste is more apparently manifest in rural areas whose material conditions partially warrant its prevalence, whereas in urban areas it exists mostly in the ideological terrain. In building its analysis, the study has employed a combination of objectivist and subjectivist approaches to capture the material and ideological existence of caste and caste politics in Sinhalese society. Therefore, methods such as in-depth interviews, observation, and collection of demographical and interpretive data from secondary sources were used for this study. The paper has been situated in a critical theoretical framework of social inquiry in an attempt to question dominant assumptions regarding such meta-labels as ‘Capitalism’ and ‘Democracy’, and also the supposed emancipatory function of religion (focusing on Buddhism).Keywords: Buddhism, capitalism, caste, democracy, Sri Lanka
Procedia PDF Downloads 134914 In-Situ Formation of Particle Reinforced Aluminium Matrix Composites by Laser Powder Bed Fusion of Fe₂O₃/AlSi12 Powder Mixture Using Consecutive Laser Melting+Remelting Strategy
Authors: Qimin Shi, Yi Sun, Constantinus Politis, Shoufeng Yang
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In-situ preparation of particle-reinforced aluminium matrix composites (PRAMCs) by laser powder bed fusion (LPBF) additive manufacturing is a promising strategy to strengthen traditional Al-based alloys. The laser-driven thermite reaction can be a practical mechanism to in-situ synthesize PRAMCs. However, introducing oxygen elements through adding Fe₂O₃ makes the powder mixture highly sensitive to form porosity and Al₂O₃ film during LPBF, bringing challenges to producing dense Al-based materials. Therefore, this work develops a processing strategy combined with consecutive high-energy laser melting scanning and low-energy laser remelting scanning to prepare PRAMCs from a Fe₂O₃/AlSi12 powder mixture. The powder mixture consists of 5 wt% Fe₂O₃ and the remainder AlSi12 powder. The addition of 5 wt% Fe₂O₃ aims to achieve balanced strength and ductility. A high relative density (98.2 ± 0.55 %) was successfully obtained by optimizing laser melting (Emelting) and laser remelting surface energy density (Eremelting) to Emelting = 35 J/mm² and Eremelting = 5 J/mm². Results further reveal the necessity of increasing Emelting, to improve metal liquid’s spreading/wetting by breaking up the Al₂O₃ films surrounding the molten pools; however, the high-energy laser melting produced much porosity, including H₂₋, O₂₋ and keyhole-induced pores. The subsequent low-energy laser remelting could close the resulting internal pores, backfill open gaps and smoothen solidified surfaces. As a result, the material was densified by repeating laser melting and laser remelting layer by layer. Although with two-times laser scanning, the microstructure still shows fine cellular Si networks with Al grains inside (grain size of about 370 nm) and in-situ nano-precipitates (Al₂O₃, Si, and Al-Fe(-Si) intermetallics). Finally, the fine microstructure, nano-structured dispersion strengthening, and high-level densification strengthened the in-situ PRAMCs, reaching yield strength of 426 ± 4 MPa and tensile strength of 473 ± 6 MPa. Furthermore, the results can expect to provide valuable information to process other powder mixtures with severe porosity/oxide-film formation potential, considering the evidenced contribution of laser melting/remelting strategy to densify material and obtain good mechanical properties during LPBF.Keywords: densification, laser powder bed fusion, metal matrix composites, microstructures, mechanical properties
Procedia PDF Downloads 155913 Modeling of Anisotropic Hardening Based on Crystal Plasticity Theory and Virtual Experiments
Authors: Bekim Berisha, Sebastian Hirsiger, Pavel Hora
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Advanced material models involving several sets of model parameters require a big experimental effort. As models are getting more and more complex like e.g. the so called “Homogeneous Anisotropic Hardening - HAH” model for description of the yielding behavior in the 2D/3D stress space, the number and complexity of the required experiments are also increasing continuously. In the context of sheet metal forming, these requirements are even more pronounced, because of the anisotropic behavior or sheet materials. In addition, some of the experiments are very difficult to perform e.g. the plane stress biaxial compression test. Accordingly, tensile tests in at least three directions, biaxial tests and tension-compression or shear-reverse shear experiments are performed to determine the parameters of the macroscopic models. Therefore, determination of the macroscopic model parameters based on virtual experiments is a very promising strategy to overcome these difficulties. For this purpose, in the framework of multiscale material modeling, a dislocation density based crystal plasticity model in combination with a FFT-based spectral solver is applied to perform virtual experiments. Modeling of the plastic behavior of metals based on crystal plasticity theory is a well-established methodology. However, in general, the computation time is very high and therefore, the computations are restricted to simplified microstructures as well as simple polycrystal models. In this study, a dislocation density based crystal plasticity model – including an implementation of the backstress – is used in a spectral solver framework to generate virtual experiments for three deep drawing materials, DC05-steel, AA6111-T4 and AA4045 aluminum alloys. For this purpose, uniaxial as well as multiaxial loading cases, including various pre-strain histories, has been computed and validated with real experiments. These investigations showed that crystal plasticity modeling in the framework of Representative Volume Elements (RVEs) can be used to replace most of the expensive real experiments. Further, model parameters of advanced macroscopic models like the HAH model can be determined from virtual experiments, even for multiaxial deformation histories. It was also found that crystal plasticity modeling can be used to model anisotropic hardening more accurately by considering the backstress, similar to well-established macroscopic kinematic hardening models. It can be concluded that an efficient coupling of crystal plasticity models and the spectral solver leads to a significant reduction of the amount of real experiments needed to calibrate macroscopic models. This advantage leads also to a significant reduction of computational effort needed for the optimization of metal forming process. Further, due to the time efficient spectral solver used in the computation of the RVE models, detailed modeling of the microstructure are possible.Keywords: anisotropic hardening, crystal plasticity, micro structure, spectral solver
Procedia PDF Downloads 313