Search results for: formidable mechanism
1939 CO2 Gas Solubility and Foam Generation
Authors: Chanmoly Or, Kyuro Sasaki, Yuichi Sugai, Masanori Nakano, Motonao Imai
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Cold drainage mechanism of oil production is a complicated process which involves with solubility and foaming processes. Laboratory experiments were carried out to investigate the CO2 gas solubility in hexadecane (as light oil) and the effect of depressurization processes on microbubble generation. The experimental study of sensitivity parameters of temperature and pressure on CO2 gas solubility in hexadecane was conducted at temperature of 20 °C and 50 °C and pressure ranged 2.0–7.0 MPa by using PVT (RUSKA Model 2370) apparatus. The experiments of foamy hexadecane were also prepared by depressurizing from saturated pressure of 6.4 MPa and temperature of 50 °C. The experimental results show the CO2 gas solubility in hexadecane linearly increases with increasing pressure. At pressure 4.5 MPa, CO2 gas dissolved in hexadecane 2.5 mmol.g-1 for temperature of 50 °C and 3.5 mmol.g-1 for temperature of 20 °C. The bubbles of foamy hexadecane were observed that most of large bubbles were coalesced shortly whereas the small one keeps presence. The experimental result of foamy hexadecane indicated large depressurization step (∆P) produces high quality of foam with high microbubble distribution.Keywords: CO2 gas solubility, depressurization process, foamy hexadecane, microbubble distribution
Procedia PDF Downloads 4871938 Design Modification of Lap Joint of Fiber Metal Laminates (CARALL)
Authors: Shaher Bano, Samia Fida, Asif Israr
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The synergistic effect of properties of metals and fibers reinforced laminates has diverted attention of the world towards use of robust composite materials known as fiber-metal laminates in many high performance applications. In this study, modification of an adhesively bonded joint as a single lap joint of carbon fibers based CARALL FML has done to increase interlaminar shear strength of the joint. The effect of different configurations of joint designs such as spews, stepped and modification in adhesive by addition of nano-fillers was studied. Both experimental and simulation results showed that modified joint design have superior properties as maximum force experienced stepped joint was 1.5 times more than the simple lap joint. Addition of carbon nano-tubes as nano-fillers in the adhesive joint increased the maximum force due to crack deflection mechanism.Keywords: adhesive joint, Carbon Reinforced Aluminium Laminate (CARALL), fiber metal laminates, spews
Procedia PDF Downloads 2261937 ECOSURF EH3 - A Taq DNA Polymerase Enhancer
Authors: Kimberley Phoena Fan, Yu Zhang
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ECOSURF™ EH-3 Surfactant (EH3) is a nonionic surfactant and has superior wetting and excellent oil removal properties. It is biodegradable with low toxicity and meets or exceeds US EPA Design for the Environment Criteria, and is widely used as a home cleaner, commercial and industrial degreaser. We have recently found that EH3 also possesses a special function which is characterized as an enhancer to Taq DNA polymerase and ameliorator to reduce the effects of PCR inhibitors, i.e., blood, urea, Guanidinium thiocyanate, Humic acids, polyphenol, and Polysaccharides. This is a new kind of PCR enhancer that does not work on relieving secondary structures of GC-rich templates. We have compared EH3’s effects on Taq DNA Polymerase along with other well-known enhancers, such as DMSO, betaine, and BSA, using GC rich or deficient template and found that, unlike DMSO and Betaine, the EH3 boosting effect on PCR reaction is not through reducing Tm. The results show the same increase of PCR products regardless of the GC contents or secondary structures. The mechanism of EH3 enhancing PCR is through its direct interaction with or stimulation of the DNA polymerase and making the enzymes more resistant to inhibitors in the presence of EH3. This phenomenon has first been observed for EH3, a new type of PCR enzyme enhancer. Subsequent research also shows that a series of similar surfactants boost Taq DNA polymerase as well.Keywords: EH3, DNA, polymerase, enhancer, raw biological samples
Procedia PDF Downloads 1261936 3D Shape Knitting: Loop Alignment on a Surface with Positive Gaussian Curvature
Authors: C. T. Cheung, R. K. P. Ng, T. Y. Lo, Zhou Jinyun
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This paper aims at manipulating loop alignment in knitting a three-dimensional (3D) shape by its geometry. Two loop alignment methods are introduced to handle a surface with positive Gaussian curvature. As weft knitting is a two-dimensional (2D) knitting mechanism that the knitting cam carrying the feeders moves in two directions only, left and right, the knitted fabric generated grows in width and length but not in depth. Therefore, a 3D shape is required to be flattened to a 2D plane with surface area preserved for knitting. On this flattened plane, dimensional measurements are taken for loop alignment. The way these measurements being taken derived two different loop alignment methods. In this paper, only plain knitted structure was considered. Each knitted loop was taken as a basic unit for loop alignment in order to achieve the required geometric dimensions, without the inclusion of other stitches which give textural dimensions to the fabric. Two loop alignment methods were experimented and compared. Only one of these two can successfully preserve the dimensions of the shape.Keywords: 3D knitting, 3D shape, loop alignment, positive Gaussian curvature
Procedia PDF Downloads 3361935 Effect Mechanisms of Aromatic Plants: Effects on Intestinal Health and Broiler Feeding
Authors: Ozlem Durna Aydin, Gultekin Yildiz
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Antibiotics are microbial metabolites with low molecular weight produced by fungi and algae, inhibiting the development of other microorganisms even in low growth. Antibiotics have been used as growth factors in animal feeds for many years. They prohibited; because of increased residue problem and increased resistance to antibiotics in bacteria due to prolonged use. Aromatic plants and extracts have attracted the attention of scientists nowadays due to positive reasons such as confidence of the community to the products those are coming from nature, desire to consume, and no residue problems. Plant extracts are obtained from aromatic plants, and they come forward with antifungal, antibacterial, antiviral, antioxidant and antilipidemic properties. It has been stated that intestinal histomorphology and microbiosis are positively affected by the use of plant extract in feeds. In the present day, aromatic plants and extracts are a remarkable research field with intriguing unknowns in the field of animal nutrition, and they continue to exist in the journal in vitro and in vivo studies.Keywords: aromatic plant, broilers, extract mechanism of action, intestinal health
Procedia PDF Downloads 1561934 Measuring Government’s Performance (Services) Oman Service Maturity Model (OSMM)
Authors: Angie Al Habib, Khalid Al Siyabi
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To measure or asses any government’s efficiency we need to measure the performance of this government in regards to the quality of the service it provides. Using a technological platform in service provision became a trend and a public demand. It is also a public need to make sure these services are aligned to values and to the whole government’s strategy, vision and goals as well. Providing services using technology tools and channels can enhance the internal business process and also help establish many essential values to government services like transparency and excellence, since in order to establish e-services many standards and policies must be put in place to enable the handing over of decision making to a mature system oriented mechanism. There was no doubt that the Sultanate of Oman wanted to enhance its services and move it towards automation and establishes a smart government as well as links its services to life events. Measuring government efficiency is very essential in achieving social security and economic growth, since it can provide a clear dashboard of all projects and improvements. Based on this data we can improve the strategies and align the country goals to them.Keywords: government, maturity, Oman, performance, service
Procedia PDF Downloads 3581933 Soil Arching Effect in Columnar Embankments: A Numerical Study
Authors: Riya Roy, Anjana Bhasi
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Column-supported embankments provide a practical and efficient solution for construction on soft soil due to the low cost and short construction times. In the recent years, geosynthetic have been used in combination with column systems to support embankments. The load transfer mechanism in these systems is a combination of soil arching effect, which occurs between columns and membrane effect of the geosynthetic. This paper aims at the study of soil arching effect on columnar embankments using finite element software, ABAQUS. An axisymmetric finite element model is generated and using this model, parametric studies are carried out. Thus the effects of various factors such as height of embankment fill, elastic modulus of pile and tensile stiffness of geosynthetic, on soil arching have been studied. The development of negative skin friction along the pile-soil interface have also been studied and the results obtained from this study are compared with the current design methods.Keywords: ABAQUS, geosynthetic, negative skin friction, soil arching
Procedia PDF Downloads 3711932 A Similar Image Retrieval System for Auroral All-Sky Images Based on Local Features and Color Filtering
Authors: Takanori Tanaka, Daisuke Kitao, Daisuke Ikeda
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The aurora is an attractive phenomenon but it is difficult to understand the whole mechanism of it. An approach of data-intensive science might be an effective approach to elucidate such a difficult phenomenon. To do that we need labeled data, which shows when and what types of auroras, have appeared. In this paper, we propose an image retrieval system for auroral all-sky images, some of which include discrete and diffuse aurora, and the other do not any aurora. The proposed system retrieves images which are similar to the query image by using a popular image recognition method. Using 300 all-sky images obtained at Tromso Norway, we evaluate two methods of image recognition methods with or without our original color filtering method. The best performance is achieved when SIFT with the color filtering is used and its accuracy is 81.7% for discrete auroras and 86.7% for diffuse auroras.Keywords: data-intensive science, image classification, content-based image retrieval, aurora
Procedia PDF Downloads 4411931 Design and Motion Control of a Two-Wheel Inverted Pendulum Robot
Authors: Shiuh-Jer Huang, Su-Shean Chen, Sheam-Chyun Lin
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Two-wheel inverted pendulum robot (TWIPR) is designed with two-hub DC motors for human riding and motion control evaluation. In order to measure the tilt angle and angular velocity of the inverted pendulum robot, accelerometer and gyroscope sensors are chosen. The mobile robot’s moving position and velocity were estimated based on DC motor built in hall sensors. The control kernel of this electric mobile robot is designed with embedded Arduino Nano microprocessor. A handle bar was designed to work as steering mechanism. The intelligent model-free fuzzy sliding mode control (FSMC) was employed as the main control algorithm for this mobile robot motion monitoring with different control purpose adjustment. The intelligent controllers were designed for balance control, and moving speed control purposes of this robot under different operation conditions and the control performance were evaluated based on experimental results.Keywords: balance control, speed control, intelligent controller, two wheel inverted pendulum
Procedia PDF Downloads 2131930 The Promotion of AI Technology to Financial Development in China
Authors: Li Yong
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Using the data of 135 financial institutions in China from 2018 to 2022, this paper deeply analyzes the underlying theoretical mechanism of artificial intelligence (AI) technology promoting financial development and examines the impact of AI technology on the digital transformation performance of financial enterprises. It is found that the level of AI technology has a significant positive impact on the development of finance. Compared with the impact on the expansion of financial scale, AI technology plays a greater role in improving the performance of financial institutions, reflecting the trend characteristics of the current AI technology to promote the evolution of financial structure. By investigating the intermediary transmission effects, we found that AI technology plays a positive role in promoting the performance of financial institutions by reducing operating costs and improving customer satisfaction, but its function in innovating financial products and mitigating financial risks is relatively limited. In addition, the promotion of AI technology in financial development has significant heterogeneity in terms of the type, scale, and attributes of financial institutions.Keywords: artificial intelligence technology, financial development, China, heterogeneity
Procedia PDF Downloads 511929 Numerical Model for Investigation of Recombination Mechanisms in Graphene-Bonded Perovskite Solar Cells
Authors: Amir Sharifi Miavaghi
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It is believed recombination mechnisms in graphene-bonded perovskite solar cells based on numerical model in which doped-graphene structures are employed as anode/cathode bonding semiconductor. Moreover, the dark-light current density-voltage density-voltage curves are investigated by regression analysis. Loss mechanisms such as back contact barrier, deep surface defect in the adsorbent layer is determined by adapting the simulated cell performance to the measurements using the differential evolution of the global optimization algorithm. The performance of the cell in the connection process includes J-V curves that are examined at different temperatures and open circuit voltage (V) under different light intensities as a function of temperature. Based on the proposed numerical model and the acquired loss mechanisms, our approach can be used to improve the efficiency of the solar cell further. Due to the high demand for alternative energy sources, solar cells are good alternatives for energy storage using the photovoltaic phenomenon.Keywords: numerical model, recombination mechanism, graphen, perovskite solarcell
Procedia PDF Downloads 591928 Design of an Electric Vehicle Model with a Dynamo Drive Setup Using Model-Based Development (MBD) (EV Using MBD)
Authors: Gondu Vykunta Rao, Madhuri Bayya, Aruna Bharathi M., Paramesw Chidamparam, B. Murali
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The increase in software content in today’s electric vehicles is increasing attention to having vast, unique topographies from low emission to high efficiency, whereas the chemical batteries have huge short comes, such as limited cycle life, power density, and cost. As for understanding and visualization, the companies are turning toward the virtual vehicle to test their design in software which is known as a simulation in the loop (SIL). In this project, in addition to the electric vehicle (EV) technology, we are adding a dynamo with the vehicle for regenerative braking. Traditionally the principle of dynamos is used in lighting the purpose of the bicycle. Here by using the same mechanism, we are running the vehicle as well as charging the vehicle from system-level simulation to the model in the loop and then to the Hardware in Loop (HIL) by using model-based development.Keywords: electric vehicle, simulation in the loop (SIL), model in loop (MIL), hardware in loop (HIL), dynamos, model-based development (MBD), permanent magnet synchronous motor (PMSM), current control (CC), field-oriented control (FOC), regenerative braking
Procedia PDF Downloads 1051927 English Language Acquisition and Flipped Classroom
Authors: Yuqing Sun
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Nowadays, English has been taught in many countries as a second language. One of the major ways to learn this language is through the class teaching. As in the field of second language acquisition, there are many factors to affect its acquisition processes, such as the target language itself, a learner’s personality, cognitive factor, language transfer, and the outward factors (teaching method, classroom, environmental factor, teaching policy, social environment and so on). Flipped Classroom as a newly developed classroom model has been widely used in language teaching classroom, which was, to some extent, accepted by teachers and students for its effect. It distinguishes itself from the traditional classroom for its focus on the learner and its great importance attaching to the personal learning process and the application of technology. The class becomes discussion-targeted, and the class order is somewhat inverted since the teaching process is carried out outside the class, while the class is only for knowledge-internalization. This paper will concentrate on the influences of the flipped classroom, as a classroom affecting factor, on the the process of English acquisition by the way of case studies (English teaching class in China), and the analysis of the mechanism of the flipped classroom itself to propose some feasible advice of promoting the the effectiveness of English acquisition.Keywords: second language acquisition, English, flipped classroom, case
Procedia PDF Downloads 3901926 A Coupling Study of Public Service Facilities and Land Price Based on Big Data Perspective in Wuxi City
Authors: Sisi Xia, Dezhuan Tao, Junyan Yang, Weiting Xiong
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Under the background of Chinese urbanization changing from incremental development to stock development, the completion of urban public service facilities is essential to urban spatial quality. As public services facilities is a huge and complicated system, clarifying the various types of internal rules associated with the land market price is key to optimizing spatial layout. This paper takes Wuxi City as a representative sample location and establishes the digital analysis platform using urban price and several high-precision big data acquisition methods. On this basis, it analyzes the coupling relationship between different public service categories and land price, summarizing the coupling patterns of urban public facilities distribution and urban land price fluctuations. Finally, the internal mechanism within each of the two elements is explored, providing the reference of the optimum layout of urban planning and public service facilities.Keywords: public service facilities, land price, urban spatial morphology, big data
Procedia PDF Downloads 2011925 Syndrome of Irreversible Lithium-Effectuated Neurotoxicity: Case Report and Review of Literature
Authors: David J. Thomson, Joshua C. J. Chew
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Background: Syndrome of Irreversible Lithium-Effectuated Neurotoxicity (SILENT) is a rare complication of lithium toxicity that typically causes irreversible cerebellar dysfunction. These patients may require hemodialysis and extensive supports in the intensive care. Methods: A review was performed on the available literature of SILENT with a focus on current pathophysiological hypotheses and advances in treatment. Articles were restricted to the English language. Results: Although the exact mechanism is unclear, CNS demyelination, especially in the cerebellum, was seen on the brain biopsies of a proportion of patients. There is no definitive management of SILENT but instead current management is focused on primary and tertiary prevention – detection of those at risk, and rehabilitation post onset of neurological deficits. Conclusions: This review draws conclusions from a limited amount of available literature, most of which are isolated case reports. Greater awareness of SILENT and further investigation into the risk factors and pathogenesis are required so this serious and irreversible syndrome may be avoided.Keywords: lithium toxicity, pathogenesis, SILENT, syndrome of irreversible lithium-effectuated neurotoxicity
Procedia PDF Downloads 4901924 Language Processing of Seniors with Alzheimer’s Disease: From the Perspective of Temporal Parameters
Authors: Lai Yi-Hsiu
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The present paper aims to examine the language processing of Chinese-speaking seniors with Alzheimer’s disease (AD) from the perspective of temporal cues. Twenty healthy adults, 17 healthy seniors, and 13 seniors with AD in Taiwan participated in this study to tell stories based on two sets of pictures. Nine temporal cues were fetched and analyzed. Oral productions in Mandarin Chinese were compared and discussed to examine to what extent and in what way these three groups of participants performed with significant differences. Results indicated that the age effects were significant in filled pauses. The dementia effects were significant in mean duration of pauses, empty pauses, filled pauses, lexical pauses, normalized mean duration of filled pauses and lexical pauses. The findings reported in the current paper help characterize the nature of language processing in seniors with or without AD, and contribute to the interactions between the AD neural mechanism and their temporal parameters.Keywords: language processing, Alzheimer’s disease, Mandarin Chinese, temporal cues
Procedia PDF Downloads 4371923 Network Connectivity Knowledge Graph Using Dwave Quantum Hybrid Solvers
Authors: Nivedha Rajaram
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Hybrid Quantum solvers have been given prime focus in recent days by computation problem-solving domain industrial applications. D’Wave Quantum Computers are one such paragon of systems built using quantum annealing mechanism. Discrete Quadratic Models is a hybrid quantum computing model class supplied by D’Wave Ocean SDK - a real-time software platform for hybrid quantum solvers. These hybrid quantum computing modellers can be employed to solve classic problems. One such problem that we consider in this paper is finding a network connectivity knowledge hub in a huge network of systems. Using this quantum solver, we try to find out the prime system hub, which acts as a supreme connection point for the set of connected computers in a large network. This paper establishes an innovative problem approach to generate a connectivity system hub plot for a set of systems using DWave ocean SDK hybrid quantum solvers.Keywords: quantum computing, hybrid quantum solver, DWave annealing, network knowledge graph
Procedia PDF Downloads 1151922 Identifying Dominant Anaerobic Microorganisms for Degradation of Benzene
Authors: Jian Peng, Wenhui Xiong, Zheng Lu
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An optimal recipe of amendment (nutrients and electron acceptors) was developed and dominant indigenous benzene-degrading microorganisms were characterized in this study. Lessons were learnt from the development of the optimal amendment recipe: (1) salinity and substantial initial concentration of benzene were detrimental for benzene biodegradation; (2) large dose of amendments can shorten the lag time for benzene biodegradation occurrence; (3) toluene was an essential co-substance for promoting benzene degradation activity. The stable isotope probing study identified incorporation 13C from 13C-benzene into microorganisms, which can be considered as a direct evidence of the occurrence of benzene biodegradation. The dominant mechanism for benzene removal was identified by quantitative polymerase chain reaction analysis to be nitrate reduction. Microbial analyses (denaturing gradient gel electrophoresis and 16S ribosomal RNA) demonstrated that members of genus Dokdonella spp., Pusillimonas spp., and Advenella spp. were predominant within the microbial community and involved in the anaerobic benzene bioremediation.Keywords: benzene, enhanced anaerobic bioremediation, stable isotope probing, biosep biotrap
Procedia PDF Downloads 3331921 Establishing Taiwan's Marine Space Planning System
Authors: Wen-Yan Chiau
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Taiwan passed the 'Basic Ocean Act' in November 2019, and in accordance with Article 4 of its provisions, the government should draft a decree on ocean space planning (MSP). In the past few years, although Taiwan has passed the 'Coastal Zone Management Act' and the 'Spatial Planning Act', in the face of multiple use of marine areas, it still lacks a comprehensive marine area use blueprint and a fundamental mechanism for multi-purpose use planning management. In particular, Taiwan's active development of offshore wind power is facing this problem, and it is impossible to fully reconcile the use of each domain and the public welfare through a holistic system, highlighting the urgency of the establishment of MSP system. Therefore, this article will review relevant Taiwan laws and regulations, refer to important international initiatives and experiences, and participate in the exchange of practical experience in international conference(s), and propose adequate framework, principles, procedures, and promotion strategies on MSP. Possible solutions to promote sustainable and wise use in Taiwan's waters will also be suggested for comments.Keywords: basic ocean act, coastal zone management act, marine spatial planning, spatial planning act, Taiwan
Procedia PDF Downloads 1231920 Biosorption of Ni (II) Using Alkaline-Treated Rice Husk
Authors: Khanom Simarani
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Rice husk has been widely reported as a good sorbent for heavy metals. Pre treatment of rice husk minimizes cellulose crystallinity and increases the surface area thus ensuring better adsorption capacity. Commercial base and natural base-treated rice husk were used to investigate the potential of Ni(II) adsorption from synthetic solutions and waste water in batch systems. Effects of process variables such as pH, contact time, adsorbent dose, initial Ni (II) concentration were studied. Optimum Ni (II) adsorption was observed at pH 6 within 60 min of contact time. Experimental data showed increased amount of adsorbed Ni(II) with increasing adsorbent dose and decreased percent of adsorption with increasing initial Ni(II) concentration. Kinetic isotherms (Langmuir, Freundlich) were also applied. Biosorption mechanism of rice husk was analyzed using SEM/EDS, FT-IR, and XRD. The results revealed that natural base produced from agroindustrial waste could be used as efficient as commercial bases during pre treatment rice husk in removing Ni(II) from waste waters within 15 min.Keywords: Nickel removal, adsorbent, heavy metal, biomass
Procedia PDF Downloads 2831919 Influence of Grain Shape, Size and Grain Boundary Diffusion on High Temperature Oxidation of Metal
Authors: Sneha Samal, Iva Petrikova, Bohdana Marvalova
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Influence of grain size, shape and grain boundary diffusion at high temperature oxidation of pure metal is investigated as the function of microstructure evolution in this article. The oxidized scale depends on the geometrical parameter of the metal-scale system and grain shape, size, diffusion through boundary layers and influence of the contamination. The creation of the inner layer and the morphological structure develops from the internal stress generated during the growth of the scale. The oxidation rate depends on the cation and anion mobile transport of the metal in the inward and outward direction of the diffusion layer. Oxidation rate decreases with decreasing the grain size of the pure metal, whereas zinc deviates from this principle. A strong correlation between the surface roughness evolution, grain size, crystalline properties and oxidation mechanism of the oxidized metal was established.Keywords: high temperature oxidation, pure metals, grain size, shape and grain boundary
Procedia PDF Downloads 4831918 UWB Open Spectrum Access for a Smart Software Radio
Authors: Hemalatha Rallapalli, K. Lal Kishore
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In comparison to systems that are typically designed to provide capabilities over a narrow frequency range through hardware elements, the next generation cognitive radios are intended to implement a broader range of capabilities through efficient spectrum exploitation. This offers the user the promise of greater flexibility, seamless roaming possible on different networks, countries, frequencies, etc. It requires true paradigm shift i.e., liberalization over a wide band of spectrum as well as a growth path to more and greater capability. This work contributes towards the design and implementation of an open spectrum access (OSA) feature to unlicensed users thus offering a frequency agile radio platform that is capable of performing spectrum sensing over a wideband. Thus, an ultra-wideband (UWB) radio, which has the intelligence of spectrum sensing only, unlike the cognitive radio with complete intelligence, is named as a Smart Software Radio (SSR). The spectrum sensing mechanism is implemented based on energy detection. Simulation results show the accuracy and validity of this method.Keywords: cognitive radio, energy detection, software radio, spectrum sensing
Procedia PDF Downloads 4111917 Behavior of Fibre Reinforced Polymer Composite with Nano-Ceramic Particle under Ballistic Impact and Quasi-Static Punch-Shear Loading
Authors: K. Rajalakshmi, A. Vasudevan
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The performance of Fibre Reinforced Polymer composite with the nano-ceramic particle as function of time and thickness of laminate which is subjected to ballistic impact and quasi-static punch-shear loading is investigated. The material investigated is made up of several layers of Kevlar fibres which are fabricated with nano-ceramic particles and epoxy resin by compression moulding. The ballistic impact and quasi-static punch-shear loading are studied experimentally and numerically. The failure mechanism is observed using scanning electron microscope (SEM). The result obtained in the experiment and numerical studies are compared. Due to nano size of the ceramic particle, the strength to weight ratio and penetrating resistance will improve in Fibre Reinforced Polymer composite which will have better impact property compared to ceramic plates.Keywords: ballistic impact, Kevlar, nano ceramic, penetration, polymer composite, shear plug
Procedia PDF Downloads 2791916 Failure Statistics Analysis of China’s Spacecraft in Full-Life
Authors: Xin-Yan Ji
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The historical failures data of the spacecraft is very useful to improve the spacecraft design and the test philosophies and reduce the spacecraft flight risk. A study of spacecraft failures data was performed, which is the most comprehensive statistics of spacecrafts in China. 2593 on-orbit failures data and 1298 ground data that occurred on 150 spacecraft launched from 2000 to 2016 were identified and collected, which covered the navigation satellites, communication satellites, remote sensing deep space exploration manned spaceflight platforms. In this paper, the failures were analyzed to compare different spacecraft subsystem and estimate their impact on the mission, then the development of spacecraft in China was evaluated from design, software, workmanship, management, parts, and materials. Finally, the lessons learned from the past years show that electrical and mechanical failures are responsible for the largest parts, and the key solution to reduce in-orbit failures is improving design technology, enough redundancy, adequate space environment protection measures, and adequate ground testing.Keywords: spacecraft anomalies, anomalies mechanism, failure cause, spacecraft testing
Procedia PDF Downloads 1081915 Impact of Iron Doping on Induction Heating during Spark Plasma Sintering
Authors: Hua Tan, David Salamon
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In this study, γ-Al2O3 powders doped with various amounts of iron were sintered via SPS process. Two heating modes – auto and manual mode were applied to observe the role of electrical induction on heating. Temperature, electric current, and pulse pattern were experimented with grade iron γ-Al2O3 powders. Phase transformation of γ to α -Al2O3 serves as a direct indicator of internal temperature, independently on measured outside temperature. That pulsing in SPS is also able to induce internal heating due to its strong electromagnetic field when dopants are conductive metals (e.g., iron) is proofed during SPS. Density and microstructure were investigated to explain the mechanism of induction heating. In addition, the role of electric pulsing and strong electromagnetic field on internal heating (induction heating) were compared and discussed. Internal heating by iron doping within electrically nonconductive samples is able to decrease sintering temperature and save energy, furthermore it is one explanation for unique features of this material fabrication technology.Keywords: spark plasma sintering, induction heating, alumina, microstructure
Procedia PDF Downloads 3261914 Failure Analysis of a Medium Duty Vehicle Leaf Spring
Authors: Gül Çevik
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This paper summarizes the work conducted to assess the root cause of the failure of a medium commercial vehicle leaf spring failed in service. Macro- and micro-fractographic analyses by scanning electron microscope as well as material verification tests were conducted in order to understand the failure mechanisms and root cause of the failure. Findings from the fractographic analyses indicated that failure mechanism is fatigue. Crack initiation was identified to have occurred from a point on the top surface near to the front face and to the left side. Two other crack initiation points were also observed, however, these cracks did not propagate. The propagation mode of the fatigue crack revealed that the cyclic loads resulting in crack initiation and propagation were unidirectional bending. Fractographic analyses have also showed that the root cause of the fatigue crack initiation and propagation was loading the part above design stress. Material properties of the part were also verified by chemical composition analysis, microstructural analysis by optical microscopy and hardness tests.Keywords: leaf spring, failure analysis, fatigue, fractography
Procedia PDF Downloads 1251913 The Impact of Ionic Strength on the Adsorption Behavior of Anionic and Cationic Dyes on Low Cost Biosorbent
Authors: Abdallah Bouguettoucha, Derradji Chebli, Sara Aga, Agueniou Fazia
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The objective of this study was to looking for alternative materials (low cost) for the adsorption of textile dyes and optimizes the type which gives optimum adsorption and provides an explanation of the mechanism involved in the adsorption process. Adsorption of Orange II and Methylene blue on H2SO4 traited cone of Pinus brutia, was carried out at different initial concentrations of the dye (20, 50 and 100 mg / L) and at tow initial pH, pH 1 and 10 respectively. The models of Langmuir, Freundlich and Sips were used in this study to analyze the obtained results of the adsorption isotherm. PCB-0M had high adsorption capacities namely 32.8967 mg/g and 128.1651 mg/g, respectively for orange II and methylene blue and further indicated that the removal of dyes increased with increase in the ionic strength of solution, this was attributed to aggregation of dyes in solution. The potential of H2SO4 traited cone of Pinus brutia, an easily available and low cost material, to be used as an alternative biosorbent material for the removal of a dyes, Orange II and Methylene Bleu, from aqueous solutions was therefore confirmed.Keywords: Methylene blue, orange II, cones of pinus brutia, adsorption
Procedia PDF Downloads 2771912 Survey of Intrusion Detection Systems and Their Assessment of the Internet of Things
Authors: James Kaweesa
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The Internet of Things (IoT) has become a critical component of modern technology, enabling the connection of numerous devices to the internet. The interconnected nature of IoT devices, along with their heterogeneous and resource-constrained nature, makes them vulnerable to various types of attacks, such as malware, denial-of-service attacks, and network scanning. Intrusion Detection Systems (IDSs) are a key mechanism for protecting IoT networks and from attacks by identifying and alerting administrators to suspicious activities. In this review, the paper will discuss the different types of IDSs available for IoT systems and evaluate their effectiveness in detecting and preventing attacks. Also, examine the various evaluation methods used to assess the performance of IDSs and the challenges associated with evaluating them in IoT environments. The review will highlight the need for effective and efficient IDSs that can cope with the unique characteristics of IoT networks, including their heterogeneity, dynamic topology, and resource constraints. The paper will conclude by indicating where further research is needed to develop IDSs that can address these challenges and effectively protect IoT systems from cyber threats.Keywords: cyber-threats, iot, intrusion detection system, networks
Procedia PDF Downloads 711911 Comparison of Various Control Methods for an Industrial Multiproduct Fractionator
Authors: Merve Aygün Esastürk, Deren Ataç Yılmaz, Görkem Oğur, Emre Özgen Kuzu, Sadık Ödemiş
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Hydrocracker plants are one of the most complicated and most profitable units in the refinery process. It takes long chain paraffinic hydrocarbons as feed and turns them into smaller and more valuable products, mainly kerosene and diesel under high pressure with the excess amount of hydrogen. Controlling the product qualities well directly contributes to the unit profit. Control of a plant is mainly based on PID and MPC controllers. Controlling the reaction section is important in terms of reaction severity. However, controlling the fractionation section is more crucial since the end products are separated in fractionation section. In this paper, the importance of well-configured base layer control mechanism, composed of PID controllers, is highlighted. For this purpose, two different base layer control scheme is applied in a hydrocracker fractionator column performances of schemes, which is a direct contribution to better product quality, are compared.Keywords: controller, distillation, configuration selection, hydrocracker, model predictive controller, proportional-integral-derivative controller
Procedia PDF Downloads 4331910 Growth Mechanism and Sensing Behaviour of Sn Doped ZnO Nanoprisms Prepared by Thermal Evaporation Technique
Authors: Sudip Kumar Sinha, Saptarshi Ghosh
Abstract:
While there’s a perpetual buzz around zinc oxide (ZnO) superstructures for their unique optical features, the versatile material has been constantly utilized to manifest tailored electronic properties through rendition of distinct morphologies. And yet, the unorthodox approach of implementing the novel 1D nanostructures of ZnO (pristine or doped) for volatile sensing applications has ample scope to accommodate new unconventional morphologies. In the last two decades, solid-state sensors have attracted much curiosity for their relevance in identifying pollutant, toxic and other industrial gases. In particular gas sensors based on metal oxide semiconducting (wide Eg) nanomaterials have recently attracted intensive attention owing to their high sensitivity and fast response and recovery time. These materials when exposed to air, the atmospheric O2 dissociates and get absorb on the surface of the sensors by trapping the outermost shell electrons. Finally a depleted zone on the surface of the sensors is formed, that enhances the potential barrier height at grain boundary . Once a target gas is exposed to the sensor, the chemical interaction between the chemisorbed oxygen and the specific gas liberates the trapped electrons. Therefore altering the amount of adsorbate is a considerable approach to improve the sensitivity of any target gas/vapour molecule. Likewise, this study presents a spontaneous but self catalytic creation of Sn-doped ZnO hexagonal nanoprisms on Si (100) substrates through thermal evaporation-condensation method, and their subsequent deployment for volatile sensing. In particular, the sensors were utilized to detect molecules of ethanol, acetone and ammonia below their permissible exposure limits which returned sensitivities of around 85%, 80% and 50% respectively. The influence of Sn concentration on the growth, microstructural and optical properties of the nanoprisms along with its role in augmenting the sensing parameters has been detailed. The single-crystalline nanostructures have a typical diameter ranging from 300 to 500 nm and a length that extends up to few micrometers. HRTEM images confirmed the hexagonal crystallography for the nanoprisms, while SAED pattern asserted the single crystalline nature. The growth habit is along the low index <0001>directions. It has been seen that the growth mechanism of the as-deposited nanostructures are directly influenced by varying supersaturation ratio, fairly high substrate temperatures, and specified surface defects in certain crystallographic planes, all acting cooperatively decide the final product morphology. Room temperature photoluminescence (PL) spectra of this rod like structures exhibits a weak ultraviolet (UV) emission peak at around 380 nm and a broad green emission peak in the 505 nm regime. An estimate of the sensing parameters against dispensed target molecules highlighted the potential for the nanoprisms as an effective volatile sensing material. The Sn-doped ZnO nanostructures with unique prismatic morphology may find important applications in various chemical sensors as well as other potential nanodevices.Keywords: gas sensor, HRTEM, photoluminescence, ultraviolet, zinc oxide
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