Search results for: surface acoustic wave

Authors: Shidvash Vakilipour, Mehdi Habibnia, Rouzbeh Riazi, Masoud Mohammadi, Mohammad H. Sabour

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The flow field passing through a highly loaded low pressure (LP) turbine cascade is numerically investigated at design and off-design conditions. The Field Operation And Manipulation (OpenFOAM) platform is used as the computational Fluid Dynamics (CFD) tool. Firstly, the influences of grid resolution on the results of k-ε, k-ω, and LES turbulence models are investigated and compared with those of experimental measurements. A numerical pressure under-shoot is appeared near the end of blade pressure surface which is sensitive to grid resolution and flow turbulence modeling. The LES model is able to resolve separation on a coarse and fine grid resolutions. Secondly, the off-design flow condition is modeled by negative and positive inflow incidence angles. The numerical experiments show that a separation bubble generated on blade pressure side is predicted by LES. The total pressure drop is also been calculated at incidence angle between -20◦ and +8◦. The minimum total pressure drop is obtained by k-ω and LES at the design point.

Keywords: low pressure turbine, off-design performance, openFOAM, turbulence modeling, flow separation

Procedia PDF Downloads 359

Authors: Jian-Xiu Wan, Yao Yin

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In complex terrain and poor geological conditions areas, Railway, highway and other transportation constructions are still strongly developing. However, various geological disasters happened such as landslide, rock heap and so on. According to the results of geological investigation, the form of skirt (trapezoidal), semicircle and triangle rock heaps are mainly due to complex internal force and external force, in a certain extent, which is related to the terrain, the nature of the rock mass, the supply area and the surface shape of rock heap. Combined with the above factors, discrete element numerical simulation of rock mass is established under different terrain conditions based on 3DEC, and accelerated formation process of rock heap under seismic action is simulated. The fragmentation structure supply area is calculated, in which the most dangerous area is located. At the same time, the formation mechanism and development process are studied in different terrain conditions, and the structure of rock heap is judged by section, which can provide a strong theoretical and technical support for the prevention and control of geological disasters.

Keywords: 3DEC, fragmentation structure, rock heap, slope, seismic action

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Authors: Priyanka Dutta Chowdhury

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A globalized connected world, calling loud for a composite culture, was still not able to erase the pain of a desired nationalism based on cultural identity. In the South Asian region, the random drawing of the boundaries without taking the ethnic aspect into consideration have always challenged the very basis of the existence of certain groups. The urge to reunify with the fellow brothers on both sides of the border have always called for a chaos and schism in the countries of this region. Sometimes this became a tool to bargain with the state and find a favorable position in the power structure on the basis of cultural identity. In Pakistan and Afghanistan, the Pakhtuns who are divided across the border of the two countries, from the inception of creation of Pakistan have posed various challenges and hampered the growth of a consolidated nation. The Pakhtuns or Pashtuns of both Pakistan and Afghanistan have a strong cultural affinity which blurs their physical distancing and calls for a nationalism based on this ethnic affiliation. Both the sides wanted to create Pakhtunistan unifying all the Pakhtuns of the region. For long, this group have denied to accept the Durand line separating the two. This was an area of concern especially for the Pakhtuns of Pakistan torn between the decision either to join Afghanistan, create a nation of their own or be a part of Pakistan. This ethnic issue became a bone of contention between the two countries. Later, though well absorbed and recognized in the respective countries, they have fought for their identity and claimed for a dominant position in the politics of the nations. Because of the porous borders often influx of refugees was seen especially during Afghan Wars and later many extremists’ groups were born from them especially the Taliban. In the recent string of events, when the Taliban, who are mostly Pakhtuns ethnically, came in power in Afghanistan, a wave of sympathy arose in Pakistan. This gave a strengthening position to the religious Pakhtuns across the border. It is to be noted here that a fragmented Pakhtun identity between the religious and seculars were clearly visible, voicing for their place in the political hierarchy of the country with a vision distinct from each other especially in Pakistan. In this context the paper tries to evaluate the reasons for this cultural turmoil between the countries and this ethnic group. It also aims to analyze the concept of how the identity politics still holds its relevance in the contemporary world. Additionally, the recent trend of fragmented identity points towards instrumentalization of this ethnic groups, who are engaged in the bargaining process with the state for a robust position in the power structure. In the end, the paper aims to deduct from the theoretical conditions of identity politics, whether this is a primordial or a situational tool to have a visibility in the power structure of the contemporary world.

Keywords: cultural identity, identity politics, instrumentalization of identity pakhtuns, power structure

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Authors: Yau-Luen Ng, Nathan Banka, Santosh Devasia

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In this paper, a method based on soft artificial cilia is introduced to separate particles based on size and mass. In nature, cilia are used for fluid propulsion in the mammalian circulatory system, as well as for swimming and size-selective particle entrainment for feeding in microorganisms. Inspired by biological cilia, an array of artificial cilia was fabricated using Polydimethylsiloxane (PDMS) to simulate the actual motion. A row of four individually-controlled magnetic artificial cilia in a semi-circular channel are actuated by the magnetic fields from four permanent magnets. Each cilium is a slender rectangular cantilever approximately 13mm long made from a composite of PDMS and carbonyl iron particles. A time-varying magnetic force is achieved by periodically varying the out-of-plane distance from the permanent magnets to the cilia, resulting in large-amplitude deflections of the cilia that can be used to drive fluid motion. Previous results have shown that this system of individually-controlled magnetic cilia can generate effective mixing flows; the purpose of the present work is to apply the individual cilia control to a particle separation task. Based on the observed beating patterns of cilia arrays in nature, the experimental beating patterns were selected as a metachronal wave, in which a fixed phase lead or lag is imposed between adjacent cilia. Additionally, the beating frequency was varied. For each set of experimental parameters, the channel was filled with water and polyethylene microspheres introduced at the center of the cilia array. Two types of particles were used: large red microspheres with density 0.9971 g/cm³ and 850-1000 μm avg. diameter, and small blue microspheres with density 1.06 g/cm³ and diameter 30 μm. At low beating frequencies, all particles were propelled in the mean flow direction. However, the large particles were observed to reverse directions above about 4.8 Hz, whereas reversal of the small particle transport direction did not occur until 6 Hz. Between these two transition frequencies, the large and small particles can be separated as they move in opposite directions. The experimental results show that selecting an appropriate cilia beating pattern can lead to selective transport of neutrally-buoyant particles based on their size. Importantly, the separation threshold can be chosen dynamically by adjusting the actuation frequency. However, further study is required to determine the range of particle sizes that can be effectively separated for a given system geometry.

Keywords: magnetic cilia, particle separation, tunable separation, soft actutors

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Authors: Manuel de Pazos-Liano, Manuel Cifuentes-Antonio, Juan Fisac-Gozalo, Sara Perales-Momparler, Carlos Martinez-Montero

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The first-ever game in the Wanda Metropolitano Stadium, the new home of the Club Atletico de Madrid, was played on September 16, 2017, thanks to the work of a multidisciplinary team that made it possible to combine urban development with sustainability goals. The new football ground sits on a 1.2 km² land owned by the city of Madrid. Its construction has dramatically increased the sealed area of the site (transforming the runoff coefficient from 0.35 to 0.9), and the surrounding sewer network has no capacity for that extra flow. As an alternative to enlarge the existing 2.5 m diameter pipes, it was decided to detain runoff on site by means of an integrated and durable infrastructure that would not blow up the construction cost nor represent a burden on the municipality’s maintenance tasks. Instead of the more conventional option of building a large concrete detention tank, the decision was taken on the use of pervious pavement on the 3013 car parking spaces for sub-surface water storage, a solution aligned with the city water ordinance and the Madrid + Natural project. Making the idea a reality, in only five months and during the summer season (which forced to pour the porous concrete only overnight), was a challenge never faced before in Spain, that required of innovation both at the material as well as the machinery side. The process consisted on: a) defining the characteristics required for the porous concrete (compressive strength of 15 N/mm2 and 20% voids); b) testing of different porous concrete dosages at the construction company laboratory; c) stablishing the cross section in order to provide structural strength and sufficient water detention capacity (20 cm porous concrete over a 5 cm 5/10 gravel, that sits on a 50 cm coarse 40/50 aggregate sub-base separated by a virgin fiber polypropylene geotextile fabric); d) hydraulic computer modelling (using the Full Hydrograph Method based on the Wallingford Procedure) to estimate design peak flows decrease (an average of 69% at the three car parking lots); e) use of a variety of machinery for the application of the porous concrete to achieve both structural strength and permeable surface (including an inverse rotating rolling imported from USA, and the so-called CMI, a sliding concrete paver used in the construction of motorways with rigid pavements); f) full-scale pilots and final construction testing by an accredited laboratory (pavement compressive strength average value of 15 N/mm2 and 0,0032 m/s permeability). The continuous testing and innovating construction process explained in detail within this article, allowed for a growing performance with time, finally proving the use of the CMI valid also for large porous car park applications. All this process resulted in a successful story that converts the Wanda Metropolitano Stadium into a great demonstration site that will help the application of the Spanish Royal Decree 638/2016 (it also counts with rainwater harvesting for grass irrigation).

Keywords: construction machinery, permeable carpark, porous concrete, SUDS, sustainable develpoment

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Authors: Yifan Zheng, Jinmin Zhu, Jiji Li, Gulling Li, Huahong Shi

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Secondary microplastics originate from the fragmentation of large plastics, and weathering is supposed to be the main cause of fragmentation. In this study, we investigated burrows and burrowing invertebrates on Styrofoam floats from the mariculture areas of China’s coastal waters. Various burrows were found on the submerged surface of Styrofoam floats and could be divided into ‘I’, ‘S’, ‘J’, and ‘Y’ types based on the burrow entrance number and passage curvature. Different invertebrate species, including 5 isopods, 8 clamworms, and 12 crabs, were found inside the burrows. Micro-foams were found in the bodies of these burrowers, with an average abundance of 4.2 ± 0.3 (isopod), 6.9 ± 2.0 (clamworm), and 3.0 ± 0.5 (crab) micro-foams per individual. In the laboratory, we observed the boring process of crabs in abandoned floats. Field and laboratory evidence suggested that these invertebrates bored various burrows. The total volume of crab burrows on a 3-year-used float was estimated to be 2.6 × 10³ cm³, producing 4.1 × 10⁸ microplastics. This study highlights the critical role of bioerosion in destroying man-made substrates and prompting microplastic pollution.

Keywords: burrowing invertebrate, mariculture area, styrofoam float, fragmentation, microplastics

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Authors: H. S. Haroyan, V. R. Tadevosyan

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High gain broadband plasmonic slot nano-antenna has been considered. The theory of plasmonic slot nano-antenna (PSNA) has been developed. The analytical model takes into account also the electrical field inside the metal due to imperfectness of metal in optical range, as well as numerical investigation based on FEM method has been realized. It should be mentioned that Yagi-Uda configuration improves directivity in the plane of structure. In contrast, in this paper the possibility of directivity improvement of proposed PSNA in perpendicular plane of structure by using reflection metallic surface placed under the slot in fixed distance has been demonstrated. It is well known that a directivity improvement brings to the antenna gain increasing. This method of diagram improving is also well known from RF antenna design theory. Moreover the improvement of directivity in the perpendicular plane gives more flexibility in such application as improving the light and atom, ion, molecule interactions by using such type of plasmonic slot antenna. By the analogy of dipole type optical antennas the widening of working wavelengths has been realized by using bowtie geometry of slots, which made the antenna broadband.

Keywords: broadband antenna, high gain, slot nano-antenna, plasmonics.

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Authors: Amit Keshav

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Waste bone, produced in large quantity (8-10 kg./day) from a slaughterhouse, could be a cheap (cost $0.20 per kg) substitute for commercial catalysts. In the present work, catalyst for esterification reaction was prepared from waste bone and characterized by various techniques. Bone was deoiled and then sulfonated. Fourier-transform infrared spectroscopy (FTIR) spectra of prepared catalyst predicted –OH vibration at 3416 and 1630 cm⁻¹, S-O stretching at 1124 cm⁻¹ and intense bands of hydroxypatite in a region between 500 and 700 cm⁻¹. X-ray diffraction (XRD) predicts peaks of hydroxyapatite, CaO, and tricalcium phosphate. Scanning electron microscope (SEM) was employed to reveal the presence of non-uniformity deposited fine particles on the catalyst surface that represents active acidic sites. The prepared catalyst was employed to study its performance on esterification reaction between acrylic acid and ethanol in a molar ratio of 1:1 at a set temperature of 60 °C. Results show an equilibrium conversion of 49% which is matched to the commercial catalysts employed in literature. Thus waste bone could be a good catalyst for acrylic acid removal from waste industrial streams via the process of esterification.Keywords— Heterogeneous catalyst, characterization, esterification, equilibrium conversion

Keywords: heterogeneous catalyst, characterization, esterification, equilibrium conversion

Procedia PDF Downloads 141

Authors: Shuo Li, Yannick Coffinier, Chann Lagadec, Fabrizio Cleri, Katsuhiko Nishiguchi, Akira Fujiwara, Soo Hyeon Kim, Nicolas Clément

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The need for single cell detection and analysis techniques has increased in the past decades because of the heterogeneity of individual living cells, which increases the complexity of the pathogenesis of malignant tumors. In the search for early cancer detection, high-precision medicine and therapy, the technologies most used today for sensitive detection of target analytes and monitoring the variation of these species are mainly including two types. One is based on the identification of molecular differences at the single-cell level, such as flow cytometry, fluorescence-activated cell sorting, next generation proteomics, lipidomic studies, another is based on capturing or detecting single tumor cells from fresh or fixed primary tumors and metastatic tissues, and rare circulating tumors cells (CTCs) from blood or bone marrow, for example, dielectrophoresis technique, microfluidic based microposts chip, electrochemical (EC) approach. Compared to other methods, EC sensors have the merits of easy operation, high sensitivity, and portability. However, despite various demonstrations of low limits of detection (LOD), including aptamer sensors, arrayed EC sensors for detecting single-cell have not been demonstrated. In this work, a new technique based on 20-nm-thick nanopillars array to support cells and keep them at ideal recognition distance for redox-labeled aptamers grafted on the surface. The key advantages of this technology are not only to suppress the false positive signal arising from the pressure exerted by all (including non-target) cells pushing on the aptamers by downward force but also to stabilize the aptamer at the ideal hairpin configuration thanks to a confinement effect. With the first implementation of this technique, a LOD of 13 cells (with5.4 μL of cell suspension) was estimated. In further, the nanosupported cell technology using redox-labeled aptasensors has been pushed forward and fully integrated into a single-cell electrochemical aptasensor array. To reach this goal, the LOD has been reduced by more than one order of magnitude by suppressing parasitic capacitive electrochemical signals by minimizing the sensor area and localizing the cells. Statistical analysis at the single-cell level is demonstrated for the recognition of cancer cells. The future of this technology is discussed, and the potential for scaling over millions of electrodes, thus pushing further integration at sub-cellular level, is highlighted. Despite several demonstrations of electrochemical devices with LOD of 1 cell/mL, the implementation of single-cell bioelectrochemical sensor arrays has remained elusive due to their challenging implementation at a large scale. Here, the introduced nanopillar array technology combined with redox-labeled aptamers targeting epithelial cell adhesion molecule (EpCAM) is perfectly suited for such implementation. Combining nanopillar arrays with microwells determined for single cell trapping directly on the sensor surface, single target cells are successfully detected and analyzed. This first implementation of a single-cell electrochemical aptasensor array based on Brownian-fluctuating redox species opens new opportunities for large-scale implementation and statistical analysis of early cancer diagnosis and cancer therapy in clinical settings.

Keywords: bioelectrochemistry, aptasensors, single-cell, nanopillars

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Authors: Christopher Viens, Bosko Gajic, Steve Krase

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Stick-Slip is a term that is often overused and commonly diagnosed from surface drilling parameters of torque and differential pressure, but the actual magnitude of the condition is rarely captured at the BHA level as the necessary measurements are seldom deployed. Deployment of an accurate stick-slip measurement downhole has led to an interesting discovery that goes against long held traditional drilling lore. A divide has been identified between stick-slip as independent bit and BHA conditions. This phenomenon in horizontal laterals is common, but few M/LWD systems have been able to capture it. Utilizing measurements of downhole RPM bore pressure, high-speed magnetometer data, bending moment, and continuous inclination, the wellbore spiraling phenomenon is able to be captured, quantified, and intimately tied back to systematic effects of BHA stalling and micro-sliding. An operator in the Permian Basin has identified that this phenomenon is contributing to increased tortuosity and drag. Utilizing downhole torque measurements the root causes of the stick-slip and spiraling phenomenon were identified and able to engineered out of the system.

Keywords: bending moment, downhole dynamics measurements, micro sliding, wellbore spiraling

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Authors: Seyed Abolhasan Naeini, Saeideh Mohammadi

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Time dependent settlement due to loading on soft saturated soils produces many problems such as high consolidation settlements and low consolidation rates. Also, long term consolidation settlement of soft soil underlying the embankment leads to unpredicted settlements and cracks on soil surface. Preloading method is an effective improvement method to solve this problem. Using vertical drains in preloading method is an effective method for improving soft soils. Applying deep soil mixing method on soft soils is another effective method for improving soft soils. There are little studies on using two methods of preloading and deep soil mixing simultaneously. In this paper, the concurrent effect of preloading with deep soil mixing by vertical drains is investigated through a finite element code, Plaxis2D. The influence of parameters such as deep soil mixing columns spacing, existence of vertical drains and distance between them, on settlement and stability factor of safety of embankment embedded on soft soil is investigated in this research.

Keywords: preloading, soft soil, vertical drains, deep soil mixing, consolidation settlement

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Authors: Abdurzag Kerban

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Preservation of semen had a major impact on sheep genetic breeding. The aim of this study was to evaluate the viability of ram spermatozoa after freezing pellet using cold surfaces made from cattle fat and paraffin wax. A pool of three to four ejaculates were pooled from six rams within a period of ten weeks. Semen was diluted in egg yolk-Tris diluent and processed in 0.25 ml straw and 0.1 ml pellets. Motility was evaluated after dilution, before freezing and post-thawing at 0, 1, 2 and 3 hour incubation. Viability index, acrosome integrity and leakage of intracellular enzymes (aspartat aminotransferase and alkline phosphatase) were also evaluated. Spermatozoa exhibited highly significant percentages of motility at 0, 1, 2 and 3 hours incubation after thawing and viability index in 0.25 ml straw and 0.1 ml pellets on cattle fat plate as compared to ram spermatozoa frozen on paraffin wax. In conclusion, cattle fat plate could be used as the cold surface of choice for freezing ram semen in form of pellets. Such form of frozen semen could be used as efficiently as semen frozen in straws. This simple method is economical with little expensive equipment or supplies, and may provide an efficient technique to cryopreserve ram spermatozoa in developing countries.

Keywords: ram semen, freezing, straw, pellet

Procedia PDF Downloads 589

Authors: Abdelkarim Mahdhi, Fdhila Kais, Faouzi Lamari, Zeineb Hmila, Fathi Kamoun, Maria Ángeles Esteban, Amina Bakhrouf

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Pathogenic bacteria are considered to be responsible for several infectious diseases in aquaculture. To overcome diseases in fish culture, the use of antimicrobial drugs as strategy, have been adopted. The use of probiotic was a promising approach to avoid the risk associated to pathogenic bacteria. To find a biological control treatment against pathogens, we undertook this investigation to study the maintain of the probiotic properties of Bacillus sp., such as viability, adhesive ability to abiotic surface, antibacterial activity and pathogenicity/toxicity, under marine starvation conditions. Our data revealed that the tested strains maintained their capacity to inhibit pathogens in vivo and in vitro conditions. These strains maintain their adhesive capacity to polystyrene and do not demonstrate the pathogenic or toxic effect to the host. The obtained results give insight about the effect of starvation conditions on the physiological responses of these Bacillus strains that can be considered as a potential candidate’s probiotic.

Keywords: bacillus, probiotic, cell viability, starvation conditions

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Authors: Ahmed M. Noureldin, Khaled M. Naguib

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This experimental investigation tries to identify the root cause of the black sand issue in one of the man-made lakes in a well-known Hurghada resort. The lake is nourished by the underground wells' source, which continuously empties into the Red Sea. Chemical testing was done by looking at spots of stinky black sand beneath the sandy lake surface. The findings on samples taken from several locations (wells, lake bottom sand samples, and clean sand with exact specifications as bottom sand) indicated the existence of organic sulfur bacteria that are responsible for the phenomena of black sand. Approximately 39.139 mg/kg of sulfide in the form of hydrogen sulfide was present in the lake bottom sand, while 1.145 mg/kg, before usage, was in the bare sand. The study also involved modeling with the GPS-X program for cleaning bottom sand that uses hydro cyclones as a physical-mechanical treatment method. The modeling findings indicated a Total Organic Carbon (TOC) removal effectiveness of 0.65%. The research recommended using hydro cyclones to routinely mechanically clear the sand from lake bottoms.

Keywords: man-made lakes, organic sulfur bacteria, total organic carbon, hydro cyclone

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Authors: Febrian Tegar Wicaksana, Niqmatul Kurniati, Surya Nandika

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Indonesia is one of the countries that have great number of disaster occurrence and threat because it is located in not only between three tectonic plates such as Eurasia plates, Indo-Australia plates and Pacific plates, but also in the Ring of Fire path, like earthquake, Tsunami, volcanic eruption and many more. Recently, research shows that there are potential areas that will be devastated by Tsunami in southern coast of Java. Tsunami is a series of waves in a body of water caused by the displacement of a large volume of water, generally in an ocean. When the waves enter shallow water, they may rise to several feet or, in rare cases, tens of feet, striking the coast with devastating force. The parameter for reference such as magnitude, the depth of epicentre, distance between epicentres with land, the depth of every points, when reached the shore and the growth of waves. Interaction between parameters will bring the big variance of Tsunami wave. Based on that, we can formulate preparation that needed for disaster mitigation strategies. The mitigation strategies will take the important role in an effort to reduce the number of victims and damage in the area. It will reduce the number of victim and casualties. Reducing is directed to the most difficult mobilization casualties in the tsunami disaster area like old people, sick people and disabilities people. Until now, the method that used for rescuing people from Tsunami is basic horizontal evacuation. This evacuation system is not optimal because it needs so long time and it cannot be used by people with disabilities. The writers propose to create a vertical evacuation model with an escape bunker system. This bunker system is chosen because the downward vertical evacuation is considered more efficient and faster. Especially in coastal areas without any highlands surround it. The downward evacuation system is better than upward evacuation because it can avoid the risk of erosion at the ground around the structure which can affect the building. The structure of the bunker and the evacuation process while, and even after, disaster are the main priority to be considered. The power of bunker has quake’s resistance, the durability from water stream, variety of interaction to the ground, and waterproof design. When the situation is back to normal, victim and casualties can go into the safer place. The bunker will be located near the hospital and public places, and will have wide entrance supported by large slide in it so it will ease the disabilities people. The technology of the escape bunker system is expected to reduce the number of victims who have low mobility in the Tsunami.

Keywords: escape bunker, tsunami, vertical evacuation, mitigation, disaster management

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Authors: Alebachew Halefom, Navsal Kumar, Arunava Poddar

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The purpose of this work is to specify the parameter values, the base flow index (BFI), and to rank the methods that should be used for base flow separation. Three different digital graphical approaches are chosen and used in this study for the purpose of comparison. The daily time series discharge data were collected from the site for a period of 30 years (1986 up to 2015) and were used to evaluate the algorithms. In order to separate the base flow and the surface runoff, daily recorded streamflow (m³/s) data were used to calibrate procedures and get parameter values for the basin. Additionally, the performance of the model was assessed by the use of the standard error (SE), the coefficient of determination (R²), and the flow duration curve (FDC) and baseflow indexes. The findings indicate that, in general, each strategy can be used worldwide to differentiate base flow; however, the Sliding Interval Method (SIM) performs significantly better than the other two techniques in this basin. The average base flow index was calculated to be 0.72 using the local minimum method, 0.76 using the fixed interval method, and 0.78 using the sliding interval method, respectively.

Keywords: baseflow index, digital graphical methods, streamflow, Emba Madre Watershed

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Authors: G. Hubert, S. Aubry

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The earth is constantly bombarded by cosmic rays that can be of either galactic or solar origin. Thus, humans are exposed to high levels of galactic radiation due to altitude aircraft. The typical total ambient dose equivalent for a transatlantic flight is about 50 μSv during quiet solar activity. On the contrary, estimations differ by one order of magnitude for the contribution induced by certain solar particle events. Indeed, during Ground Level Enhancements (GLE) event, the Sun can emit particles of sufficient energy and intensity to raise radiation levels on Earth's surface. Analyses of GLE characteristics occurring since 1942 showed that for the worst of them, the dose level is of the order of 1 mSv and more. The largest of these events was observed on February 1956 for which the ambient dose equivalent rate is in the orders of 10 mSv/hr. The extra dose at aircraft altitudes for a flight during this event might have been about 20 mSv, i.e. comparable with the annual limit for aircrew. The most recent GLE, occurred on September 2017 resulting from an X-class solar flare, and it was measured on the surface of both the Earth and Mars using the Radiation Assessment Detector on the Mars Science Laboratory's Curiosity Rover. Recently, Hubert et al. proposed a GLE model included in a particle transport platform (named ATMORAD) describing the extensive air shower characteristics and allowing to assess the ambient dose equivalent. In this approach, the GCR is based on the Force-Field approximation model. The physical description of the Solar Cosmic Ray (i.e. SCR) considers the primary differential rigidity spectrum and the distribution of primary particles at the top of the atmosphere. ATMORAD allows to determine the spectral fluence rate of secondary particles induced by extensive showers, considering altitude range from ground to 45 km. Ambient dose equivalent can be determined using fluence-to-ambient dose equivalent conversion coefficients. The objective of this paper is to analyze the GCR and SCR impacts on ambient dose equivalent considering a high number statistic of world-flight paths. Flight trajectories are based on the Eurocontrol Demand Data Repository (DDR) and consider realistic flight plan with and without regulations or updated with Radar Data from CFMU (Central Flow Management Unit). The final paper will present exhaustive analyses implying solar impacts on ambient dose equivalent level and will propose detailed analyses considering route and airplane characteristics (departure, arrival, continent, airplane type etc.), and the phasing of the solar event. Preliminary results show an important impact of the flight path, particularly the latitude which drives the cutoff rigidity variations. Moreover, dose values vary drastically during GLE events, on the one hand with the route path (latitude, longitude altitude), on the other hand with the phasing of the solar event. Considering the GLE occurred on 23 February 1956, the average ambient dose equivalent evaluated for a flight Paris - New York is around 1.6 mSv, which is relevant to previous works This point highlights the importance of monitoring these solar events and of developing semi-empirical and particle transport method to obtain a reliable calculation of dose levels.

Keywords: cosmic ray, human dose, solar flare, aviation

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Authors: S. P. Sharma, Som Nath Saha

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This paper presents the performance, based on exergy analysis of double flow solar air heaters with corrugated and flat plate absorber. A mathematical model of double flow solar air heater based on energy balance equations has been presented and the results obtained have been compared with that of a conventional flat-plate solar air heater. The double flow corrugated absorber solar air heater performs thermally better than the flat plate double flow and conventional flat-plate solar air heater under same operating conditions. However, the corrugated absorber leads to higher pressure drop thereby increasing pumping power. The results revealed that the energy and exergy efficiencies of double flow corrugated absorber solar air heater is much higher than conventional solar air heater with the concept involving of increase in heat transfer surface area and turbulence in air flow. The results indicate that the energy efficiency increases, however, exergy efficiency decreases with increase in mass flow rate.

Keywords: corrugated absorber, double flow, exergy efficiency, solar air heater

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Authors: Obsi Terfasa, Bhanupriya Das, Shiao-Shing Chen

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Converting coal fly ash (CFA) waste into ceramic membranes presents a promising alternative to traditional disposal methods, offering potential economic and environmental advantages that warrant further investigation. This research focuses on the creation of ceramic membranes exclusively from CFA using a uniaxial compaction technique. The membranes' properties were examined through various analytical methods: Scanning Electron Microscopy (SEM) revealed a porous and flawless membrane surface, X-Ray Diffraction (XRD) identified mullite and quartz crystalline structures, and Fourier-Transform Infrared Spectroscopy (FTIR) characterized the membrane's functional groups. Thermogravimetric analysis (TGA) determined the ideal sintering temperature to be 800°C. To evaluate its separation capabilities, the synthesized membrane was tested on wastewater from denim jeans production at 0.2 bar pressure. The results were impressive, with 97.42% removal of Chemical Oxygen Demand (COD), 95% color elimination, and a pure water flux of 4.5 Lm⁻²h⁻¹bar⁻¹. These findings suggest that CFA, a byproduct of thermal power plants, can be effectively repurposed to produce ultrafiltration membranes suitable for various industrial purification and separations.

Keywords: wastewater treatment, separator, coal fly ash, ceramic membrane, ultrafiltration

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Authors: Sao-Jeng Chao, Chia-Yun Wei, Si-Han Lai, Cheng-Yu Huang, Yu-Han Teng

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In Taiwan, the landforms are mainly dominated by mountains and hills. Many road sections of the National Highway are impossible to avoid problems such as slope excavation or slope filling. In order to increase the safety of the slope, various slope protection methods are used to stabilize the slope, especially the soil anchor technique is the most common. This study is inspired by the soil liquefaction potential map. The concept of the potential map is widely used. The typhoon, earth-rock flow, tsunami, flooded area, and the recent discussion of soil liquefaction have safety potential concepts. This paper brings the concept of safety potential to the anchored slope. Because the soil anchor inspection is only the concept of points, this study extends the concept of the point to the surface, using the Quantum GIS program to present the slope damage area, and depicts the slope appearance and soil anchor point with the slope as-built drawing. The soil anchor scores are obtained by anchor inspection data, and the low, medium and high potential areas are remitted by interpolation. Thus, the area where the anchored slope may be harmful is judged and relevant maintenance is provided. The maintenance units can thus prevent judgment and deal with the anchored slope as soon as possible.

Keywords: anchor, slope, potential map, lift-off test, existing load

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Authors: Parth Gupta, Ujjawal Singh, Shashank Kumar, Mansi Chandra, Arnab Sarkar

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Microfluidic devices have emerged as indispensable tools across various scientific disciplines, offering precise control and manipulation of fluids at the microscale. Their efficacy in flow-based research, spanning engineering, chemistry, and biology, relies heavily on the geometric design of microfluidic channels. This work introduces a novel approach to optimise these channels through Response Surface Methodology (RSM), departing from the conventional practice of addressing one parameter at a time. Traditionally, optimising microfluidic channels involved isolated adjustments to individual parameters, limiting the comprehensive understanding of their combined effects. In contrast, our approach considers the simultaneous impact of multiple parameters, employing RSM to efficiently explore the complex design space. The outcome is an innovative microfluidic channel that consumes an optimal sample volume and minimises flow time, enhancing overall efficiency. The relevance of geometric parameter optimization in microfluidic channels extends significantly in biomedical engineering. The flow characteristics of porous materials within these channels depend on many factors, including fluid viscosity, environmental conditions (such as temperature and humidity), and specific design parameters like sample volume, channel width, channel length, and substrate porosity. This intricate interplay directly influences the performance and efficacy of microfluidic devices, which, if not optimized, can lead to increased costs and errors in disease testing and analysis. In the context of biomedical applications, the proposed approach addresses the critical need for precision in fluid flow. it mitigate manufacturing costs associated with trial-and-error methodologies by optimising multiple geometric parameters concurrently. The resulting microfluidic channels offer enhanced performance and contribute to a streamlined, cost-effective process for testing and analyzing diseases. A key highlight of our methodology is its consideration of the interconnected nature of geometric parameters. For instance, the volume of the sample, when optimized alongside channel width, length, and substrate porosity, creates a synergistic effect that minimizes errors and maximizes efficiency. This holistic optimization approach ensures that microfluidic devices operate at their peak performance, delivering reliable results in disease testing. A key highlight of our methodology is its consideration of the interconnected nature of geometric parameters. For instance, the volume of the sample, when optimized alongside channel width, length, and substrate porosity, creates a synergistic effect that minimizes errors and maximizes efficiency. This holistic optimization approach ensures that microfluidic devices operate at their peak performance, delivering reliable results in disease testing. A key highlight of our methodology is its consideration of the interconnected nature of geometric parameters. For instance, the volume of the sample, when optimized alongside channel width, length, and substrate porosity, creates a synergistic effect that minimizes errors and maximizes efficiency. This holistic optimization approach ensures that microfluidic devices operate at their peak performance, delivering reliable results in disease testing.

Keywords: microfluidic device, minitab, statistical optimization, response surface methodology

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Authors: T. Imo, F. Latū, S. Aloi, J. Leung-Wai, V. Vaurasi, P. Amosa, M. A. Sheikh

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Contamination of heavy metals in coral reefs and coastal areas is a serious ecotoxicological and environmental problem due to direct runoff from anthropogenic wastes, commercial vessels, and discharge from industrial effluents. In Samoa, the information on the ecotoxicological impact of heavy metals on sediments is limited. This study presents baseline data on the concentration and distribution of heavy metals in sediments collected along the commercial and fishing ports in Samoa. Surface sediment samples were collected within the months of August-October 2013 from the 5 sites along the 2 ports. Sieved sample fractions were used for the evaluation of sediment physicochemical parameters namely pH, conductivity, organic matter, and bicarbonates of calcium. Heavy metal (Cu, Pb) analysis was achieved by flame atomic absorption spectrometry. Two heavy metals (Cu, Pb) were detected from each port with some concentration below the WHO permissible maximum concentration of environment quality standard. The results obtained from this study advocate for further studies regarding emerging threats of heavy metals on the vital marine resources which have significant importance to the livelihood of coastal societies, particularly Small Island States including Samoa.

Keywords: coastal environment, heavy metals, pollution, sediments

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Authors: Anderson dos Santos Ananias, Matheus Yuji Shigueoka, Roberto Saverio Souza Costa

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Soil and water conservation can be conceptualized as a combination of management and use methods, which have the function of protecting them against deterioration induced by anthropogenic or natural factors. Thus, the objective of this research was to evaluate the rural extension work in soil conservation carried out at Sítio do Alto in Jaboticabal-SP, through the analysis of planimetric data (latitude and longitude coordinates) and altimetric differences of the empirically constructed terraces by the rural producer and with technical guidance from CATI (Coordination of Integral Technical Assistance). A data collection procedure was carried out in the field, with GPS L1/L2, before the construction of five (5) terraces technically level and after their construction. The results showed that the greatest differences were found on terrace one (1), with a maximum latitude difference of 57 meters, the longitude of 23 m, and altitude of 2 m. These results corroborate the observations in the field, in which the presence of a great erosion caused by the incorrect construction of terrace 1 was verified rainwater to the side of the rural property, where the largest erosion furrows with the beginning of gully formation were found.

Keywords: GPS, mechanical pratice, surface runoff, erosion

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Authors: Rahul Saini, Roshan Lal

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The present paper deals with the free axisymmetric vibrations of bi-directional functionally graded circular plates using Mindlin’s plate theory and physical neutral surface. The temperature-dependent, as well as temperature-independent mechanical properties of the plate material, varies in radial and transverse directions. Also, temperature profile for one- and two-dimensional temperature variations has been obtained from the heat conduction equation. A simple computational formulation for the governing differential equation of motion for such a plate model has been derived using Hamilton's principle for the clamped and simply supported plates at the periphery. Employing the generalized differential quadrature method, the corresponding frequency equations have been obtained and solved numerically to retain their lowest three roots as the natural frequencies for the first three modes. The effect of various other parameters such as temperature profile, functionally graded indices, and boundary conditions on the vibration characteristics has been presented. In order to validate the accuracy and efficiency of the method, the results have been compared with those available in the literature.

Keywords: bi-directionally FG, GDQM, Mindlin’s circular plate, neutral axis, vibrations

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Authors: Kgantsi B. T., Ochwelwang A. R., Mathuthu M., Jegede O. A.

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Anthropogenic activities near water bodies contribute to poor water quality, which degrades the condition of the biota and elevates the risk to human health. The Vaal River is essential in supplying Gauteng and neighboring regions of South Africa with portable water for a variety of consumers and industries. Consequently, it is necessary to monitor and assess the radioactive risk in relation to the river's water quality. This study used an inductive coupled plasma mass spectrometer (ICPMS) to analyze the radionuclide activity concentration in the Vaal River, South Africa. Along with thorium and potassium, the total uranium concentration was calculated using the isotopic content of uranium. The elemental concentration of ²³⁸U, ²³⁵U, ²³⁴U, ²³²Th, and 40K were translated into activity concentrations. To assess the water safety for all users and consumers, all values were compared to world average activity concentrations 35, 30, and 400 Bqkg⁻¹ for ²³⁸U, ²³⁴Th, and ⁴⁰K, respectively, according to the UNSCEAR report. The results will serve as a database for further monitoring and evaluation of the radionuclide from the river, taking cognisance of potential health hazards.

Keywords: Val Rivers, ICPMS, uranium, risks

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Authors: Laura Bellassen, Idit Shachar

Abstract:

Multiple sclerosis (MS) is a chronic neurological disorder characterized by demyelination of the central nervous system (CNS), leading to a wide range of physical and cognitive impairments. Myeloid cells in the CNS, such microglia and border associated macrophage cells, participate in the neuroinflammation in MS. Activation of those cells in MS contributes to the inflammatory response in the CNS and recruitment of immune cells in the this compartment. SLAMF5 is a cell surface receptor that functions as a homophilic adhesion molecule, whose signaling can activate or inhibit leukocyte function. In the current study we followed the expression and function of SLAMF5 in myeloid cells in the CNS and in the periphery in the murine model for MS, the experimental autoimmune encephalomyelitis model (EAE). Our results show that SLAMF5 deficiency or blocking decreases the expression of activation molecules and costimulatory molecules such as MHCII and CD80, resulting in delayed onset and reduced progression of the disease. Moreover, blocking SLAMF5 in peripheral monocytes derived from MS patients and iPSC-derived microglia cells, controls the expression of HLA-DR and CD80. Thus, SLAMF5 is a regulator of myeloid cells function and can serve as a therapeutic target in autoimmune disorders as Multiple Sclerosis.

Keywords: multiple sclerosis, EAE model, myeloid cells, new antibody, neuroimmunology

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Authors: N. Allouache, O. Rahli

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Solar radiation is by far the largest and the most world’s abundant, clean, and permanent energy source. In recent years, many promising technologies have been developed to harness the sun's energy. These technologies help in environmental protection, economizing energy, and sustainable development, which are the major issues of the world. One of these important technologies is the solar refrigerating machines that make use of either absorption or adsorption technologies. In this present work, the adsorbent bed is modelized and optimized using different working pairs, such as zeolite-water, silica gel-water, activated carbon-ammonia, calcium chlorid-ammonia, activated carbon fiber- methanol and activated carbon AC35-methanol. The results show that the enhancement of the heat and mass transfer depends on the properties of the working pair; the performances of the adsorption cycle are essentially influenced by the choice of the adsorbent-adsorbate pair. The system can operate successfully for optimal parameters such as the evaporator, condenser, and generating temperatures. The activated carbon is the best adsorbent due to its high surface area and micropore volume.

Keywords: adsorbent bed, heat and mass transfer, numerical analysis, working pairs

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Authors: Udaya Kumar

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The aim of this paper is to discuss recent research conducted in experimental studies related to the process of the iron smelting. The paper will discuss issues related to the selection of iron ore, structure of furnace, making of tuyeres, fashioning of blowers and firing temperatures through experiments conducted recently and scientific analyses of experimental work. Experiments were conducted in order to investigate iron smelting techniques used at the Early Historic site of Nathara-Ki-Pal. (73°47’E; 24°16N is located about 70 km south-east of Udaipur city). Geographically, Nathara-Ki-Pal has located the foot hills of Aravalli’s. Iron ore and iron slag can be seen on the surface of the site. The remains of 4 broken furnaces were recovered during excavations (2007 and 2008) and the site was excavated by Prof. Pandey from the Department of Archaeology of the Institute of Rajasthan studies, Rajasthan Vidyapeeth University. This shows that the site of Nathara-Ki-Pal was a center of iron smelting. Results of experiments performed both in the field reconstruction of a bloomery furnace and in the laboratory are discussed.

Keywords: experimental studies, furnace, smelting techniques, making of tuyeres

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Authors: J. Suwanprateeb, F. Thammarakcharoen

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Calcium phosphate coating (CaP) has been employed for protein delivery, but the typical direct protein adsorption on the coating led to low incorporation content and fast release of the protein from the coating. By using bovine serum albumin (BSA) as a model protein, rapid biomimetic co-precipitation between calcium phosphate and BSA was employed to control the distribution of BSA within calcium phosphate coating during biomimetic formation on titanium surface for only 6 h at 50 oC in an accelerated calcium phosphate solution. As a result, the amount of BSA incorporation and release duration could be increased by using a rapid biomimetic co-precipitation technique. Up to 43 fold increases in the BSA incorporation content and the increase from 6 h to more than 360 h in release duration compared to typical direct adsorption technique were observed depending on the initial BSA concentration used during co-precipitation (1, 10, and 100 microgram/ml). From X-ray diffraction and Fourier transform infrared spectroscopy studies, the coating composition was not altered with the incorporation of BSA by this rapid biomimetic co-precipitation and mainly comprised octacalcium phosphate and hydroxyapatite. However, the microstructure of calcium phosphate crystals changed from straight, plate-like units to curved, plate-like units with increasing BSA content.

Keywords: biomimetic, Calcium Phosphate Coating, protein, titanium

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Authors: T. Taşköprü, M. Zor, E. Turan

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The advantages of nickel oxide as an electrochromic material are its good contrast of transmittance and its suitable use as a secondary electrochromic film with WO3 for electrochromic devices. Electrochromic nickel oxide film was prepared by using a simple and inexpensive chemical deposition bath (CBD) technique onto fluorine-doped tin oxide (FTO) coated glass substrates from nickel nitrate solution. The films were ace centered cubic NiO with preferred orientation in the (2 0 0) direction. The electrochromic (EC) properties of the films were studied as a function of pH (8, 9, 10 and 11) in an aqueous alkaline electrolyte (0.3 M KOH) using cyclic voltammetry (CV). The EC cell was formed with the following configuration; FTO/nickel oxide film/0.3 M KOH/Pt The potential was cycled from 0.1 to 0.6V at diffferent potential sweep rates in the range 10- 50 mV/s. The films exhibit anodic electrochromism, changing colour from transparent to black.CV results of a nickel oxide film showed well-resolved anodic current peak at potential; 45 mV and cathodic peak at potential 28 mV. The structural, morphological, and optical changes in NiO film following the CV were investigated by means of X-ray diffractometer (XRD), field emission electron microscopy (FESEM) and UV-Vis- NIR spectrophotometry. No change was observed in XRD, besides surface morphology undergoes change due to the electrical discharge. The change in tansmittance between the bleached and colored state is 68% for the film deposited with pH=11 precursor.

Keywords: nickel oxide, XRD, SEM, cyclic voltammetry

Procedia PDF Downloads 303