Search results for: electrical double layer capacitor
990 Modeling of Tsunami Propagation and Impact on West Vancouver Island, Canada
Authors: S. Chowdhury, A. Corlett
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Large tsunamis strike the British Columbia coast every few hundred years. The Cascadia Subduction Zone, which extends along the Pacific coast from Vancouver Island to Northern California is one of the most seismically active regions in Canada. Significant earthquakes have occurred in this region, including the 1700 Cascade Earthquake with an estimated magnitude of 9.2. Based on geological records, experts have predicted a 'great earthquake' of a similar magnitude within this region may happen any time. This earthquake is expected to generate a large tsunami that could impact the coastal communities on Vancouver Island. Since many of these communities are in remote locations, they are more likely to be vulnerable, as the post-earthquake relief efforts would be impacted by the damage to critical road infrastructures. To assess the coastal vulnerability within these communities, a hydrodynamic model has been developed using MIKE-21 software. We have considered a 500 year probabilistic earthquake design criteria including the subsidence in this model. The bathymetry information was collected from Canadian Hydrographic Services (CHS), and National Oceanic Atmospheric and Administration (NOAA). The arial survey was conducted using a Cessna-172 aircraft for the communities, and then the information was converted to generate a topographic digital elevation map. Both survey information was incorporated into the model, and the domain size of the model was about 1000km x 1300km. This model was calibrated with the tsunami occurred off the west coast of Moresby Island on October 28, 2012. The water levels from the model were compared with two tide gauge stations close to the Vancouver Island and the output from the model indicates the satisfactory result. For this study, the design water level was considered as High Water Level plus the Sea Level Rise for 2100 year. The hourly wind speeds from eight directions were collected from different wind stations and used a 200-year return period wind speed in the model for storm events. The regional model was set for 12 hrs simulation period, which takes more than 16 hrs to complete one simulation using double Xeon-E7 CPU computer plus a K-80 GPU. The boundary information for the local model was generated from the regional model. The local model was developed using a high resolution mesh to estimate the coastal flooding for the communities. It was observed from this study that many communities will be effected by the Cascadia tsunami and the inundation maps were developed for the communities. The infrastructures inside the coastal inundation area were identified. Coastal vulnerability planning and resilient design solutions will be implemented to significantly reduce the risk.Keywords: tsunami, coastal flooding, coastal vulnerable, earthquake, Vancouver, wave propagation
Procedia PDF Downloads 131989 Identification and Quantification of Sesquiterpene Lactones of Sagebrush (Artemisia tridentate) and Its Chemical Modification
Authors: Rosemary Anibogwu, Kavita Sharma, Karl De Jesus
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Sagebrush is an abundant and naturally occurring plant in the Intermountain West region of the United States. The plant contains an array of bioactive compounds such as flavonoids, terpenoids, sterols, and phenolic acids. It is important to identify and characterize these compounds because Native Americans use sagebrush as herbal medicine. These compounds are also utilized for preventing infection in wounds, treating headaches and colds, and possess antitumor properties. This research is an exploratory study on the sesquiterpene present in the leaves of sagebrush. The leaf foliage was extracted with 100 % chloroform and 100 % methanol. The percentage yield for the crude was considerably higher in chloroform. The Thin Layer Chromatography (TLC) analysis of the crude extracted unveiled a brown band at Rf = 0.25 and a dark brown band at Rf = 0.74, along with three unknown faint bands the 254 nm UV lamp. Furthermore, the two distinct brown (Achillin) and dark brown band (Hydroxyachillin) in TLC were further utilized in the isolation of pure compounds with column chromatography. The structures of Achillin and Hydroxyachillin were elucidated based on extensive spectroscopic analysis, including TLC, High-Performance Liquid Chromatography (HPLC), 1D- and 2D-Nuclear Magnetic Resonance (NMR), and Mass Spectroscopy (MS). The antioxidant activities of crude extract and three pure compounds were evaluated in terms of their peroxyl radical scavenging by Ferric Reducing Ability of Plasma (FRAP) and 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) methods. The crude extract showed the antioxidant activity of 18.99 ± 0.51 µmol TEg -1 FW for FRAP and 11.59 ± 0.38 µmol TEg -1 FW for DPPH. The activities of Achillin, Hydroxyachillin, and Quercetagetin trimethyl ether were 13.03, 15.90 and 14.02 µmol TEg -1 FW respectively for the FRAP assay. The three purified compounds have been submitted to the National Cancer Institute 60 cancer cell line for further study.Keywords: HPLC, nuclear magnetic resonance spectroscopy, sagebrush, sesquiterpene lactones
Procedia PDF Downloads 131988 Resveratrol-Phospholipid Complex for Sustained Delivery of Resveratrol via the Skin for the Treatment of Inflammatory Diseases
Authors: Malay K. Das, Bhupen Kalita
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The poor oral bioavailability of resveratrol (RSV) due to presystemic metabolism can be avoided via dermal route of administration. The hydrophilic-lipophilic nature of resveratrol-phospholipid complex (RSVPs) favors the delivery of resveratrol via the skin. The RSVPs embedded polymeric patch with moderate adhesiveness was developed for dermal application for sustained anti-inflammatory effect. The prepared patches were evaluated for various physicochemical properties, surface morphology by SEM, TEM, and compatibility of patch components by FT-IR and DSC studies. The dermal flux of the optimized patch formulation was found to be at 4.28 ± 0.48 mg/cm2/24 h. The analysis of skin extract after permeation study revealed the presence of resveratrol, which confirmed the localization of RSVPs in the skin. The stability of RSVPs in the polymeric patch and the physiologic environment was confirmed by FE-SEM studies on the patches after drug release and skin permeation studies. The RSVPs particles released from the polymer matrix maintaining the structural integrity and permeate the keratinized horney layer of skin. The optimized patch formulation showed sustained anti-inflammatory effect (84.10% inhibition of inflammation at 24 h) in carrageenan-induced rat paw edema model compared to marketed diclofenac sodium gel (39.58% inhibition of inflammation at 24 h). The CLSM study confirmed the localization of RSVPs for a longer period, thus enabling drug targeting to the dermis for sustained anti-inflammatory effect. Histological studies with phase contrast trinocular microscope suggested no alteration of skin integrity and no evidence of the presence of inflammatory cells after exposure to the permeants. The patch was found to be safe for skin application as evaluated by Draize method for skin irritation scoring in a rabbit model. These results suggest the therapeutic efficacy of the developed patch in both acute and chronic inflammatory diseases.Keywords: resveratrol-phospholipid complex, skin delivery, sustained anti-inflammatory effect, inflammatory diseases, dermal patch
Procedia PDF Downloads 230987 Substation Automation, Digitization, Cyber Risk and Chain Risk Management Reliability
Authors: Serzhan Ashirov, Dana Nour, Rafat Rob, Khaled Alotaibi
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There has been a fast growth in the introduction and use of communications, information, monitoring, and sensing technologies. The new technologies are making their way to the Industrial Control Systems as embedded in products, software applications, IT services, or commissioned to enable integration and automation of increasingly global supply chains. As a result, the lines that separated the physical, digital, and cyber world have diminished due to the vast implementation of the new, disruptive digital technologies. The variety and increased use of these technologies introduce many cybersecurity risks affecting cyber-resilience of the supply chain, both in terms of the product or service delivered to a customer and members of the supply chain operation. US department of energy considers supply chain in the IR4 space to be the weakest link in cybersecurity. The IR4 identified the digitization of the field devices, followed by digitalization that eventually moved through the digital transformation space with little care for the new introduced cybersecurity risks. This paper will examine the best methodologies for securing the electrical substations from cybersecurity attacks due to supply chain risks, and due to digitization effort. SCADA systems are the most vulnerable part of the power system infrastructure due to digitization and due to the weakness and vulnerabilities in the supply chain security. The paper will discuss in details how create a secure supply chain methodology, secure substations, and mitigate the risks due to digitizationKeywords: cybersecurity, supply chain methodology, secure substation, digitization
Procedia PDF Downloads 64986 Electron Beam Melting Process Parameter Optimization Using Multi Objective Reinforcement Learning
Authors: Michael A. Sprayberry, Vincent C. Paquit
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Process parameter optimization in metal powder bed electron beam melting (MPBEBM) is crucial to ensure the technology's repeatability, control, and industry-continued adoption. Despite continued efforts to address the challenges via the traditional design of experiments and process mapping techniques, there needs to be more successful in an on-the-fly optimization framework that can be adapted to MPBEBM systems. Additionally, data-intensive physics-based modeling and simulation methods are difficult to support by a metal AM alloy or system due to cost restrictions. To mitigate the challenge of resource-intensive experiments and models, this paper introduces a Multi-Objective Reinforcement Learning (MORL) methodology defined as an optimization problem for MPBEBM. An off-policy MORL framework based on policy gradient is proposed to discover optimal sets of beam power (P) – beam velocity (v) combinations to maintain a steady-state melt pool depth and phase transformation. For this, an experimentally validated Eagar-Tsai melt pool model is used to simulate the MPBEBM environment, where the beam acts as the agent across the P – v space to maximize returns for the uncertain powder bed environment producing a melt pool and phase transformation closer to the optimum. The culmination of the training process yields a set of process parameters {power, speed, hatch spacing, layer depth, and preheat} where the state (P,v) with the highest returns corresponds to a refined process parameter mapping. The resultant objects and mapping of returns to the P-v space show convergence with experimental observations. The framework, therefore, provides a model-free multi-objective approach to discovery without the need for trial-and-error experiments.Keywords: additive manufacturing, metal powder bed fusion, reinforcement learning, process parameter optimization
Procedia PDF Downloads 91985 A Hygrothermal Analysis and Structural Performance of Wood-Frame Wall Systems with Low-Permeance Exterior Insulation
Authors: Marko Spasojevic, Ying Hei Chui, Yuxiang Chen
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Increasing the level of exterior insulation in residential buildings is a popular way for improving the thermal characteristic of building enclosure and reducing heat loss. However, the layout and properties of materials composing the wall have a great effect on moisture accumulation within the wall cavity, long-term durability of a wall as well as the structural performance. A one-dimensional hygrothermal modeling has been performed to investigate moisture condensation risks and the drying capacity of standard 2×4 and 2×6 light wood-frame wall assemblies including exterior low-permeance extruded polystyrene (XPS) insulation. The analysis considered two different wall configurations whereby the rigid insulation board was placed either between Oriented Strand Board (OSB) sheathing and the stud or outboard to the structural sheathing. The thickness of the insulation varied between 0 mm and 50 mm and the analysis has been conducted for eight different locations in Canada, covering climate zone 4 through zone 8. Results show that the wall configuration with low-permeance insulation inserted between the stud and OSB sheathing accumulates more moisture within the stud cavity, compared to the assembly with the same insulation placed exterior to the sheathing. On the other hand, OSB moisture contents of the latter configuration were markedly higher. Consequently, the analysis of hygrothermal performance investigated and compared moisture accumulation in both the OSB and stud cavity. To investigate the structural performance of the wall and the effect of soft insulation layer inserted between the sheathing and framing, forty nail connection specimens were tested. Results have shown that both the connection strength and stiffness experience a significant reduction as the insulation thickness increases. These results will be compared with results from a full-scale shear wall tests in order to investigate if the capacity of shear walls with insulated sheathing would experience a similar reduction in structural capacities.Keywords: hygrothermal analysis, insulated sheathing, moisture performance, nail joints, wood shear wall
Procedia PDF Downloads 128984 Influence of Climate Change on Landslides in Northeast India: A Case Study
Authors: G. Vishnu, T. V. Bharat
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Rainfall plays a major role in the stability of natural slopes in tropical and subtropical regions. These slopes usually have high slope angles and are stable during the dry season. The critical rainfall intensity that might trigger a landslide may not be the highest rainfall. In addition to geological discontinuities and anthropogenic factors, water content, suction, and hydraulic conductivity also play a role. A thorough geotechnical investigation with the principles of unsaturated soil mechanics is required to predict the failures in these cases. The study discusses three landslide events that had occurred in residual hills of Guwahati, India. Rainfall data analysis, history image analysis, land use, and slope maps of the region were analyzed and discussed. The landslide occurred on June (24, 26, and 28) 2020, on the respective sites, but the highest rainfall was on June (6 and 17) 2020. The factors that lead to the landslide occurrence is the combination of critical events initiated with rainfall, causing a reduction in suction. The sites consist of a mixture of rocks and soil. The slope failure occurs due to the saturation of the soil layer leading to loss of soil strength resulting in the flow of the entire soil rock mass. The land-use change, construction activities, other human and natural activities that lead to faster disintegration of rock mass may accelerate the landslide events. Landslides in these slopes are inevitable, and the development of an early warning system (EWS) to save human lives and resources is a feasible way. The actual time of failure of a slope can be better predicted by considering all these factors rather than depending solely on the rainfall intensities. An effective EWS is required with less false alarms in these regions by proper instrumentation of slope and appropriate climatic downscaling.Keywords: early warning system, historic image analysis, slope instrumentation, unsaturated soil mechanics
Procedia PDF Downloads 114983 Topography Effects on Wind Turbines Wake Flow
Authors: H. Daaou Nedjari, O. Guerri, M. Saighi
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A numerical study was conducted to optimize the positioning of wind turbines over complex terrains. Thus, a two-dimensional disk model was used to calculate the flow velocity deficit in wind farms for both flat and complex configurations. The wind turbine wake was assessed using the hybrid methods that combine CFD (Computational Fluid Dynamics) with the actuator disc model. The wind turbine rotor has been defined with a thrust force, coupled with the Navier-Stokes equations that were resolved by an open source computational code (Code_Saturne V3.0 developed by EDF) The simulations were conducted in atmospheric boundary layer condition considering a two-dimensional region located at the north of Algeria at 36.74°N longitude, 02.97°E latitude. The topography elevation values were collected according to a longitudinal direction of 1km downwind. The wind turbine sited over topography was simulated for different elevation variations. The main of this study is to determine the topography effect on the behavior of wind farm wake flow. For this, the wake model applied in complex terrain needs to selects the singularity effects of topography on the vertical wind flow without rotor disc first. This step allows to determine the existence of mixing scales and friction forces zone near the ground. So, according to the ground relief the wind flow waS disturbed by turbulence and a significant speed variation. Thus, the singularities of the velocity field were thoroughly collected and thrust coefficient Ct was calculated using the specific speed. In addition, to evaluate the land effect on the wake shape, the flow field was also simulated considering different rotor hub heights. Indeed, the distance between the ground and the hub height of turbine (Hhub) was tested in a flat terrain for different locations as Hhub=1.125D, Hhub = 1.5D and Hhub=2D (D is rotor diameter) considering a roughness value of z0=0.01m. This study has demonstrated that topographical farm induce a significant effect on wind turbines wakes, compared to that on flat terrain.Keywords: CFD, wind turbine wake, k-epsilon model, turbulence, complex topography
Procedia PDF Downloads 563982 Wastewater Treatment and Bio-Electricity Generation via Microbial Fuel Cell Technology Operating with Starch Proton Exchange Membrane
Authors: Livinus A. Obasi, Augustine N. Ajah
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Biotechnology in recent times has tried to develop a mechanism whereby sustainable electricity can be generated by the activity of microorganisms on waste and renewable biomass (often regarded as “negative value”) in a device called microbial fuel cell, MFC. In this paper, we established how the biocatalytic activities of bacteria on organic matter (substrates) produced some electrons with the associated removal of some water pollution parameters; Biochemical oxygen demand (BOD), chemical oxygen demand (COD) to the tune of 77.2% and 88.3% respectively from a petrochemical sanitary wastewater. The electricity generation was possible by conditioning the bacteria to operate anaerobically in one chamber referred to as the anode while the electrons are transferred to the fully aerated counter chamber containing the cathode. Power densities ranging from 12.83 mW/m2 to 966.66 mW/m2 were achieved using a dual-chamber starch membrane MFC experimental set-up. The maximum power density obtained in this research shows an improvement in the use of low cost MFC set up to achieve power production. Also, the level of organic matter removal from the sanitary waste water by the operation of this device clearly demonstrates its potential benefit in achieving an improved benign environment. The beauty of the MFCs is their potential utility in areas lacking electrical infrastructures like in most developing countries.Keywords: bioelectricity, COD, microbial fuel cell, sanitary wastewater, wheat starch
Procedia PDF Downloads 257981 Investigation of Municipal Solid Waste Incineration Filter Cake as Minor Additional Constituent in Cement Production
Authors: Veronica Caprai, Katrin Schollbach, Miruna V. A. Florea, H. J. H. Brouwers
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Nowadays MSWI (Municipal Solid Waste Incineration) bottom ash (BA) produced by Waste-to-Energy (WtE) plants represents the majority of the solid residues derived from MSW incineration. Once processed, the BA is often landfilled resulting in possible environmental problems, additional costs for the plant and increasing occupation of public land. In order to limit this phenomenon, European countries such as the Netherlands aid the utilization of MSWI BA in the construction field, by providing standards about the leaching of contaminants into the environment (Dutch Soil Quality Decree). Commonly, BA has a particle size below 32 mm and a heterogeneous chemical composition, depending on its source. By washing coarser BA, an MSWI sludge is obtained. It is characterized by a high content of heavy metals, chlorides, and sulfates as well as a reduced particle size (below 0.25 mm). To lower its environmental impact, MSWI sludge is filtered or centrifuged for removing easily soluble contaminants, such as chlorides. However, the presence of heavy metals is not easily reduced, compromising its possible application. For lowering the leaching of those contaminants, the use of MSWI residues in combination with cement represents a precious option, due to the known retention of those ions into the hydrated cement matrix. Among the applications, the European standard for common cement EN 197-1:1992 allows the incorporation of up to 5% by mass of a minor additional constituent (MAC), such as fly ash or blast furnace slag but also an unspecified filler into cement. To the best of the author's knowledge, although it is widely available, it has the appropriate particle size and a chemical composition similar to cement, FC has not been investigated as possible MAC in cement production. Therefore, this paper will address the suitability of MSWI FC as MAC for CEM I 52.5 R, within a 5% maximum replacement by mass. After physical and chemical characterization of the raw materials, the crystal phases of the pastes are determined by XRD for 3 replacement levels (1%, 3%, and 5%) at different ages. Thereafter, the impact of FC on mechanical and environmental performances of cement is assessed according to EN 196-1 and the Dutch Soil Quality Decree, respectively. The investigation of the reaction products evidences the formation of layered double hydroxides (LDH), in the early stage of the reaction. Mechanically the presence of FC results in a reduction of 28 days compressive strength by 8% for a replacement of 5% wt., compared with the pure CEM I 52.5 R without any MAC. In contrast, the flexural strength is not affected by the presence of FC. Environmentally, the Dutch legislation for the leaching of contaminants for unshaped (granular) material is satisfied. Based on the collected results, FC represents a suitable candidate as MAC in cement production.Keywords: environmental impact evaluation, Minor additional constituent, MSWI residues, X-ray diffraction crystallography
Procedia PDF Downloads 178980 Assessment of the Effect of Building Materials on Energy Demand of Buildings in Jos: An Experimental and Numerical Approach
Authors: Zwalnan Selfa Johnson, Caleb Nanchen Nimyel, Gideon Duvuna Ayuba
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Air conditioning accounts for a significant share of the overall energy consumed in residential buildings. Solar thermal gains in buildings account for a significant component of the air conditioning load in buildings. This study compares the solar thermal gain and air conditioning load of a proposed building design with a typical conventional building in the climatic conditions of Jos, Nigeria, using a combined experimental and computational method using TRNSYS software. According to the findings of this study, the proposed design building's annual average solar thermal gains are lower compared to the reference building's average solar heat gains. The study case building's decreased solar heat gain is mostly attributable to the lower temperature of the building zones because of the greater building volume and lower fenestration ratio (ratio external opening area to the area of the external walls). This result shows that the proposed building design adjusts to the local climate better than the standard conventional construction in Jos to maintain a suitable temperature within the building. This finding means that the air-conditioning electrical energy consumption per volume of the proposed building design will be lower than that of a conventional building design.Keywords: solar heat gain, building zone, cooling energy, air conditioning, zone temperature
Procedia PDF Downloads 93979 Optimization Techniques of Doubly-Fed Induction Generator Controller Design for Reliability Enhancement of Wind Energy Conversion Systems
Authors: Om Prakash Bharti, Aanchal Verma, R. K. Saket
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The Doubly-Fed Induction Generator (DFIG) is suggested for Wind Energy Conversion System (WECS) to extract wind power. DFIG is preferably employed due to its robustness towards variable wind and rotor speed. DFIG has the adaptable property because the system parameters are smoothly dealt with, including real power, reactive power, DC-link voltage, and the transient and dynamic responses, which are needed to analyze constantly. The analysis becomes more prominent during any unusual condition in the electrical power system. Hence, the study and improvement in the system parameters and transient response performance of DFIG are required to be accomplished using some controlling techniques. For fulfilling the task, the present work implements and compares the optimization methods for the design of the DFIG controller for WECS. The bio-inspired optimization techniques are applied to get the optimal controller design parameters for DFIG-based WECS. The optimized DFIG controllers are then used to retrieve the transient response performance of the six-order DFIG model with a step input. The results using MATLAB/Simulink show the betterment of the Firefly algorithm (FFA) over other control techniques when compared with the other controller design methods.Keywords: doubly-fed induction generator, wind turbine, wind energy conversion system, induction generator, transfer function, proportional, integral, derivatives
Procedia PDF Downloads 93978 Development of Partial Discharge Defect Recognition and Status Diagnosis System with Adaptive Deep Learning
Authors: Chien-kuo Chang, Bo-wei Wu, Yi-yun Tang, Min-chiu Wu
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This paper proposes a power equipment diagnosis system based on partial discharge (PD), which is characterized by increasing the readability of experimental data and the convenience of operation. This system integrates a variety of analysis programs of different data formats and different programming languages and then establishes a set of interfaces that can follow and expand the structure, which is also helpful for subsequent maintenance and innovation. This study shows a case of using the developed Convolutional Neural Networks (CNN) to integrate with this system, using the designed model architecture to simplify the complex training process. It is expected that the simplified training process can be used to establish an adaptive deep learning experimental structure. By selecting different test data for repeated training, the accuracy of the identification system can be enhanced. On this platform, the measurement status and partial discharge pattern of each equipment can be checked in real time, and the function of real-time identification can be set, and various training models can be used to carry out real-time partial discharge insulation defect identification and insulation state diagnosis. When the electric power equipment entering the dangerous period, replace equipment early to avoid unexpected electrical accidents.Keywords: partial discharge, convolutional neural network, partial discharge analysis platform, adaptive deep learning
Procedia PDF Downloads 78977 Bacteriological Characterization of Drinking Water Distribution Network Biofilms by Gene Sequencing Using Different Pipe Materials
Authors: M. Zafar, S. Rasheed, Imran Hashmi
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Very little is concerned about the bacterial contamination in drinking water biofilm which provide a potential source for bacteria to grow and increase rapidly. So as to understand the microbial density in DWDs, a three-month study was carried out. The aim of this study was to examine biofilm in three different pipe materials including PVC, PPR and GI. A set of all these pipe materials was installed in DWDs at nine different locations and assessed on monthly basis. Drinking water quality was evaluated by different parameters and characterization of biofilm. Among various parameters are Temperature, pH, turbidity, TDS, electrical conductivity, BOD, COD, total phosphates, total nitrates, total organic carbon (TOC) free chlorine and total chlorine, coliforms and spread plate counts (SPC) according to standard methods. Predominant species were Bacillus thuringiensis, Pseudomonas fluorescens , Staphylococcus haemolyticus, Bacillus safensis and significant increase in bacterial population was observed in PVC pipes while least in cement pipes. The quantity of DWDs bacteria was directly depended on biofilm bacteria and its increase was correlated with growth and detachment of bacteria from biofilms. Pipe material also affected the microbial community in drinking water distribution network biofilm while Similarity in bacterial species was observed between systems due to same disinfectant dose, time period and plumbing pipes.Keywords: biofilm, DWDs, pipe material, bacterial population
Procedia PDF Downloads 347976 A Memristive Device with Intrinsic Rectification Behavior and Performace of Crossbar Arrays
Authors: Yansong Gao, Damith C.Ranasinghe, Siad F. Al-Sarawi, Omid Kavehei, Derek Abbott
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Passive crossbar arrays is in principle the simplest functional electrical circuit, together with memristive device in cross-point, holding great promise in future high-density, non-volatile memories. However, the greatest problem of crossbar array is the sneak path current. In this paper, we investigate one type of memristive device with intrinsic rectification behavior to address the sneak path currents. Firstly, a SPICE behavior model written in Verilog-A language of the memristive device is presented to fit experimental data published in literature. Next, systematic performance simulations including read margin and power consumption of crossbar array, which uses the self-rectifying memristive device as storage element at cross-point, with respect to different crossbar sizes, interconnect resistance, ratio of HRS/LRS (High Resistance State/ Low Resistance State), rectification ratio and different read schemes are conducted. Subsequently, Trade-offs among reading margin, power consumption, and reading schemes are analyzed to provide guidelines for circuit design. Finally, performance comparison between the memristive device with/without intrinsic rectification behavior is given to show the worthiness of this intrinsic rectification behavior.Keywords: memristive device, memristor, crossbar, RRAM, read margin, power consumption
Procedia PDF Downloads 436975 The Design of a Mixed Matrix Model for Activity Levels Extraction and Sub Processes Classification of a Work Project (Case: Great Tehran Electrical Distribution Company)
Authors: Elham Allahmoradi, Bahman Allahmoradi, Ali Bonyadi Naeini
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Complex systems have many aspects. A variety of methods have been developed to analyze these systems. The most efficient of these methods should not only be simple, but also provide useful and comprehensive information about many aspects of the system. Matrix methods are considered the most commonly methods used to analyze and design systems. Each matrix method can examine a particular aspect of the system. If these methods are combined, managers can access to more comprehensive and broader information about the system. This study was conducted in four steps. In the first step, a process model of a real project has been extracted through IDEF3. In the second step, activity levels have been attained by writing a process model in the form of a design structure matrix (DSM) and sorting it through triangulation algorithm (TA). In the third step, sub-processes have been obtained by writing the process model in the form of an interface structure matrix (ISM) and clustering it through cluster identification algorithm (CIA). In the fourth step, a mixed model has been developed to provide a unified picture of the project structure through the simultaneous presentation of activities and sub-processes. Finally, the paper is completed with a conclusion.Keywords: integrated definition for process description capture (IDEF3) method, design structure matrix (DSM), interface structure matrix (ism), mixed matrix model, activity level, sub-process
Procedia PDF Downloads 494974 Performance Comparison of Wideband Covariance Matrix Sparse Representation (W-CMSR) with Other Wideband DOA Estimation Methods
Authors: Sandeep Santosh, O. P. Sahu
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In this paper, performance comparison of wideband covariance matrix sparse representation (W-CMSR) method with other existing wideband Direction of Arrival (DOA) estimation methods has been made.W-CMSR relies less on a priori information of the incident signal number than the ordinary subspace based methods.Consider the perturbation free covariance matrix of the wideband array output. The diagonal covariance elements are contaminated by unknown noise variance. The covariance matrix of array output is conjugate symmetric i.e its upper right triangular elements can be represented by lower left triangular ones.As the main diagonal elements are contaminated by unknown noise variance,slide over them and align the lower left triangular elements column by column to obtain a measurement vector.Simulation results for W-CMSR are compared with simulation results of other wideband DOA estimation methods like Coherent signal subspace method (CSSM), Capon, l1-SVD, and JLZA-DOA. W-CMSR separate two signals very clearly and CSSM, Capon, L1-SVD and JLZA-DOA fail to separate two signals clearly and an amount of pseudo peaks exist in the spectrum of L1-SVD.Keywords: W-CMSR, wideband direction of arrival (DOA), covariance matrix, electrical and computer engineering
Procedia PDF Downloads 471973 Dietary Flaxseed Decreases Central Blood Pressure and the Concentrations of Plasma Oxylipins Associated with Hypertension in Patients with Peripheral Arterial Disease
Authors: Stephanie PB Caligiuri, Harold M Aukema, Delfin Rodriguez-Leyva, Amir Ravandi, Randy Guzman, Grant N. Pierce
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Background: Hypertension leads to cardiac and cerebral events and therefore is the leading risk factor attributed to death in the world. Oxylipins may be mediators in these events as they can regulate vascular tone and inflammation. Oxylipins are derived from fatty acids. Dietary flaxseed is rich in the n3 fatty acid, alpha-linolenic acid, and, therefore, may have the ability to change the substrate profile of oxylipins. As a result, this could alter blood pressure. Methods: A randomized, double-blinded, controlled clinical trial, the Flax-PAD trial, was used to assess the impact of dietary flaxseed on blood pressure (BP), and to also assess the relationship of plasma oxylipins to BP in 81 patients with peripheral arterial disease (PAD). Patients with PAD were chosen for the clinical trial as they are at an increased risk for hypertension and cardiac and cerebral events. Thirty grams of ground flaxseed were added to food products to consume on a daily basis for 6 months. The control food products contained wheat germ, wheat bran, and mixed dietary oils instead of flaxseed. Central BP, which is more significantly associated to organ damage, cardiac, and cerebral events versus brachial BP, was measured by pulse wave analysis at baseline and 6 months. A plasma profile of 43 oxylipins was generated using solid phase extraction, HPLC-MS/MS, and stable isotope dilution quantitation. Results: At baseline, the central BP (systolic/diastolic) in the placebo and flaxseed group were, 131/73 ± 2.5/1.4 mmHg and 128/71 ± 2.6/1.4 mmHg, respectively. After 6 months of intervention, the flaxseed group exhibited a decrease in blood pressure of 4.0/1.0 mmHg. The 6 month central BP in the placebo and flaxseed groups were, 132/74 ± 2.9/1.8 mmHg and 124/70 ± 2.6/1.6 mmHg (P<0.05). Correlation and logistic regression analyses between central blood pressure and oxylipins were performed. Significant associations were observed between central blood pressure and 17 oxylipins, primarily produced from arachidonic acid. Every 1 nM increase in 16-hydroxyeicosatetraenoic acid (HETE) increased the odds of having high central systolic BP by 15-fold, of having high central diastolic BP by 6-fold and of having high central mean arterial pressure by 15-fold. In addition, every 1 nM increase in 5,6-dihydroxyeicosatrienoic acid (DHET) and 11,12-DHET increased the odds of having high central mean arterial pressure by 45- and 18-fold, respectively. Flaxseed induced a significant decrease in these as well as 4 other vasoconstrictive oxylipins. Conclusion: Dietary flaxseed significantly lowered blood pressure in patients with PAD and hypertension. Plasma oxylipins were strongly associated with central blood pressure and may have mediated the flaxseed-induced decrease in blood pressure.Keywords: hypertension, flaxseed, oxylipins, peripheral arterial disease
Procedia PDF Downloads 468972 Adsorptive Performance of Surface Modified Montmorillonite in Vanadium Removal from Real Mine Water
Authors: Opeyemi Atiba-Oyewo, Taile Y. Leswfi, Maurice S. Onyango, Christian Wolkersdorfer
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This paper describes the preparation of surface modified montmorillonite using hexadecyltrimethylammonium bromide (HDTMA-Br) for the removal of vanadium from mine water. The adsorbent before and after adsorption was characterised by Fourier transform infra-red (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM), while the amount of vanadium adsorbed was determined by ICP-OES. The batch adsorption method was employed using vanadium concentrations in solution ranging from 50 to 320 mg/L and vanadium tailings seepage water from a South African mine. Also, solution pH, temperature and sorbent mass were varied. Results show that the adsorption capacity was affected by solution pH, temperature, sorbent mass and the initial concentration. Electrical conductivity of the mine water before and after adsorption was measured to estimate the total dissolved solids in the mine water. Equilibrium isotherm results revealed that vanadium sorption follows the Freundlich isotherm, indicating that the surface of the sorbent was heterogeneous. The pseudo-second order kinetic model gave the best fit to the kinetic experimental data compared to the first order and Elovich models. The results of this study may be used to predict the uptake efficiency of South Africa montmorillonite in view of its application for the removal of vanadium from mine water. However, the choice of this adsorbent for the uptake of vanadium or other contaminants will depend on the composition of the effluent to be treated.Keywords: adsorption, vanadium, modified montmorillonite, equilibrium, kinetics, mine water
Procedia PDF Downloads 433971 Role of Molecular Changes and Immunohistochemical in Early Detection of Liver Cancer
Authors: Fatimah A. Alhomaid
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The present study was planned to investigate the role of molecular changes and immunohistochemical in early detection of liver cancer in Saudi patients. our results were carried out on 54 patients liver cancer. We obtained our data from laboratory in King Khalid University Hospital. The specimens were taken (54) patients with liver cancer 34 male and 14 female and 2 control. The average age of varied from 37-85 years. The tumor was diagnosed as grade I in tow patients (male and female) and grade 2 in 45 patients (28 male and 17 female) while the grade 3 in 4 patients (all males). The specimens were processed for haematoxylin and eosin staining, immunohistochemical technique and flow cytometry analysis. Our study noted that most patients had adenocarcinoma which characterized by presence of signet-ring cells were very clear in advanced patients with adenocarcinoma. Our sections in adenocarcinoma in grade 2 and stage 3 had an increase in signet ring cells,an increase in the acini of glands and an increase in number of lymphocytes which spread to the muscular layer. With advancing the disease, there were haemorrhage in blood and increase in lymphocytes and increase in the number of nuclei in the tubular glands. Our study was carried on 48 patients, immunohistochemical diagnosis (CK20, PCNA, P53) and the analysis of DNA content by flow cytometry technique. Our study indicated that the presence of correlation between the immunohistochemical analysis for P53 and the grades. The reaction of P53 appeared as strong in nucleus in grades &stage 3 and appeared in other sections as dark brown pigment. Our study indicated that the absence of correlation between the immunohistochemical analysis for PCAN and the grades. In our sections there were strong reaction in the more 80% of nuclei in grade 1& stage 2. Our study indicated that the presence of correlation between the immunohistochemical analysis for CK20 and the grades. Our results indicated the presence of positive reaction in cytoplasm varied from weak to moderate in grade 3 & stage 4. Concerning the Flow cytometry technique our results indicated that the presence of correlation between the DNA and different stages of liver cancer.Keywords: cancer, CK20, DNA, cytometry analysis, liver, immunohistochemical, molecular changes, PCNA, p53
Procedia PDF Downloads 266970 Light Weight Fly Ash Based Composite Material for Thermal Insulation Applications
Authors: Bharath Kenchappa, Kunigal Shivakumar
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Lightweight, low thermal conductivity and high temperature resistant materials or the system with moderate mechanical properties and capable of taking high heating rates are needed in both commercial and military applications. A single material with these attributes is very difficult to find and one needs to come with innovative ideas to make such material system using what is available. To bring down the cost of the system, one has to be conscious about the cost of basic materials. Such a material system can be called as the thermal barrier system. This paper focuses on developing, testing and characterization of material system for thermal barrier applications. The material developed is porous, low density, low thermal conductivity of 0.1062 W/m C and glass transition temperature about 310 C. Also, the thermal properties of the developed material was measured in both longitudinal and thickness direction to highlight the fact that the material shows isotropic behavior. The material is called modified Eco-Core which uses only less than 9% weight of high-char resin in the composite. The filler (reinforcing material) is a component of fly ash called Cenosphere, they are hollow micro-bubbles made of ceramic materials. Special mixing-technique is used to surface coat the fillers with a thin layer of resin to develop a point-to-point contact of particles. One could use commercial ceramic micro-bubbles instead of Cenospheres, but it is expensive. The bulk density of Cenospheres is about 0.35 g/cc and we could accomplish the composite density of about 0.4 g/cc. One percent filler weight of 3mm length standard drywall grade fibers was used to bring the added toughness. Both thermal and mechanical characterization was performed and properties are documented. For higher temperature applications (up to 1,000 C), a hybrid system was developed using an aerogel mat. Properties of combined material was characterized and documented. Thermal tests were conducted on both the bare modified Eco-Core and hybrid materials to assess the suitability of the material to a thermal barrier application. The hybrid material system was found to meet the requirement of the application.Keywords: aerogel, fly ash, porous material, thermal barrier
Procedia PDF Downloads 111969 Arthroscopic Superior Capsular Reconstruction Using the Long Head of the Biceps Tendon (LHBT)
Authors: Ho Sy Nam, Tang Ha Nam Anh
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Background: Rotator cuff tears are a common problem in the aging population. The prevalence of massive rotator cuff tears varies in some studies from 10% to 40%. Of irreparable rotator cuff tears (IRCTs), which are mostly associated with massive tear size, 79% are estimated to have recurrent tears after surgical repair. Recent studies have shown that superior capsule reconstruction (SCR) in massive rotator cuff tears can be an efficient technique with optimistic clinical scores and preservation of stable glenohumeral stability. Superior capsule reconstruction techniques most commonly use either fascia lata autograft or dermal allograft, both of which have their own benefits and drawbacks (such as the potential for donor site issues, allergic reactions, and high cost). We propose a simple technique for superior capsule reconstruction that involves using the long head of the biceps tendon as a local autograft; therefore, the comorbidities related to graft harvesting are eliminated. The long head of the biceps tendon proximal portion is relocated to the footprint and secured as the SCR, serving to both stabilize the glenohumeral joint and maintain vascular supply to aid healing. Objective: The purpose of this study is to assess the clinical outcomes of patients with large to massive RCTs treated by SCR using LHBT. Materials and methods: A study was performed of consecutive patients with large to massive RCTs who were treated by SCR using LHBT between January 2022 and December 2022. We use one double-loaded suture anchor to secure the long head of the biceps to the middle of the footprint. Two more anchors are used to repair the rotator cuff using a single-row technique, which is placed anteriorly and posteriorly on the lateral side of the previously transposed LHBT. Results: The 3 men and 5 women had an average age of 61.25 years (range 48 to 76 years) at the time of surgery. The average follow-up was 8.2 months (6 to 10 months) after surgery. The average preoperative ASES was 45.8, and the average postoperative ASES was 85.83. The average postoperative UCLA score was 29.12. VAS score was improved from 5.9 to 1.12. The mean preoperative ROM of forward flexion and external rotation of the shoulder was 720 ± 160 and 280 ± 80, respectively. The mean postoperative ROM of forward flexion and external rotation were 1310 ± 220 and 630 ± 60, respectively. There were no cases of progression of osteoarthritis or rotator cuff muscle atrophy. Conclusion: SCR using LHBT is considered a treatment option for patients with large or massive RC tears. It can restore superior glenohumeral stability and function of the shoulder joint and can be an effective procedure for selected patients, helping to avoid progression to cuff tear arthropathy.Keywords: superior capsule reconstruction, large or massive rotator cuff tears, the long head of the biceps, stabilize the glenohumeral joint
Procedia PDF Downloads 77968 Optimal Energy Management and Environmental Index Optimization of a Microgrid Operating by Renewable and Sustainable Generation Systems
Authors: Nabil Mezhoud
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The economic operation of electric energy generating systems is one of the predominant problems in energy systems. Due to the need for better reliability, high energy quality, lower losses, lower cost and a clean environment, the application of renewable and sustainable energy sources, such as wind energy, solar energy, etc., in recent years has become more widespread. In this work, one of a bio-inspired meta-heuristic algorithm inspired by the flashing behavior of fireflies at night called the Firefly Algorithm (FFA) is applied to solve the Optimal Energy Management (OEM) and the environmental index (EI) problems of a micro-grid (MG) operating by Renewable and Sustainable Generation Systems (RSGS). Our main goal is to minimize the nonlinear objective function of an electrical microgrid, taking into account equality and inequality constraints. The FFA approach was examined and tested on a standard MG system composed of different types of RSGS, such as wind turbines (WT), photovoltaic systems (PV), and non-renewable energy, such as fuel cells (FC), micro turbine (MT), diesel generator (DEG) and loads with energy storage systems (ESS). The results are promising and show the effectiveness and robustness of the proposed approach to solve the OEM and the EI problems. The results of the proposed method have been compared and validated with those known references published recently.Keywords: renewable energy sources, energy management, distributed generator, micro-grids, firefly algorithm
Procedia PDF Downloads 76967 The Effect of Scapular Stabilization Exercises on Chronic Neck Pain
Authors: Amany Mohamed, Alaa Balbaa, Magdoline Mishel
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Background: Pain in the neck or scapular region is one of the most frequent symptoms in cervical radiculopathy, which is commonly caused by degenerative process in the spine. Purpose: To determine the effect of scapular stabilization exercises in the treatment of chronic neck pain regarding pain and disability and limitation in the range of motion. Patients and Methods: Thirty male and female patients with chronic neck pain were involved. Aged between 30-50 years old. They were randomly assigned into two groups. In group (A), patients received physical therapy program in the form of infrared, transcutaneous electrical nerve stimulation (TENS), Stretching and cervical stabilization exercises. In group (B), patients received scapular stabilization exercises in addition to the same physical therapy program. Treatment was given 3 times a week for 4 weeks. Range of motion of the cervical spine, range of motion of the scapula, neck pain and disability were assessed before and after treatment. Results: There was significant improvement in both groups (A and B) in cervical range of motion, pain and disability. Group (B) showed more significant improvement than group (A) in cervical range of motion and pain and disability. There was no significant improvement in both groups in scapular range of motion. Conclusion: Scapular stabilization exercises should be used as an integral part in the rehabilitation programKeywords: Neck pain, neck stabilization exercise, scapular stabilization exercise, chronic neck pain
Procedia PDF Downloads 302966 Feasibility Study of a Solar Solid Desiccant Cooling System in Algerian Areas
Authors: N. Hatraf, l. Merabeti, M. Abbas
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The interest in air conditioning using renewable energies is increasing. The Thermal energy produced from the solar energy can be transformed to useful cooling and heating through the thermo chemical or thermo physical processes by using thermally activated energy conversion system. Solid desiccant conditioning systems can represent a reliable alternative solution compared with other thermal cooling technologies. Their basic characteristics refer to the capability to regulate both temperature and humidity of the conditioned space in one side and to its potential in electrical energy saving in the other side. The ambient air contains so much water that very high dehumidification rates are required. For a continuous dehumidification of the process air the water adsorbed on the desiccant material has to be removed, which is done by allowing hot air to flow through the desiccant material (regeneration). Basically, solid desiccant cooling system transfers moisture from the inlet air to the silica gel by using two processes: absorption process and the regeneration process; The silica gel in the desiccant wheel which is the most important device in the system absorbs the moisture from the incoming air to the desiccant material in this case the silica gel, then it changes the heat with an rotary heat exchanger, after that the air passes through an humidifier to have the humidity required before entering to the local. The main aim of this paper is to study how the dehumidification rate, the generation temperature and many other factors influence the efficiency of a solid desiccant system by using TRNSYS software.Keywords: desiccation, dehumidification, TRNSYS, efficiency
Procedia PDF Downloads 419965 Graphic Procession Unit-Based Parallel Processing for Inverse Computation of Full-Field Material Properties Based on Quantitative Laser Ultrasound Visualization
Authors: Sheng-Po Tseng, Che-Hua Yang
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Motivation and Objective: Ultrasonic guided waves become an important tool for nondestructive evaluation of structures and components. Guided waves are used for the purpose of identifying defects or evaluating material properties in a nondestructive way. While guided waves are applied for evaluating material properties, instead of knowing the properties directly, preliminary signals such as time domain signals or frequency domain spectra are first revealed. With the measured ultrasound data, inversion calculation can be further employed to obtain the desired mechanical properties. Methods: This research is development of high speed inversion calculation technique for obtaining full-field mechanical properties from the quantitative laser ultrasound visualization system (QLUVS). The quantitative laser ultrasound visualization system (QLUVS) employs a mirror-controlled scanning pulsed laser to generate guided acoustic waves traveling in a two-dimensional target. Guided waves are detected with a piezoelectric transducer located at a fixed location. With a gyro-scanning of the generation source, the QLUVS has the advantage of fast, full-field, and quantitative inspection. Results and Discussions: This research introduces two important tools to improve the computation efficiency. Firstly, graphic procession unit (GPU) with large amount of cores are introduced. Furthermore, combining the CPU and GPU cores, parallel procession scheme is developed for the inversion of full-field mechanical properties based on the QLUVS data. The newly developed inversion scheme is applied to investigate the computation efficiency for single-layered and double-layered plate-like samples. The computation efficiency is shown to be 80 times faster than unparalleled computation scheme. Conclusions: This research demonstrates a high-speed inversion technique for the characterization of full-field material properties based on quantitative laser ultrasound visualization system. Significant computation efficiency is shown, however not reaching the limit yet. Further improvement can be reached by improving the parallel computation. Utilizing the development of the full-field mechanical property inspection technology, full-field mechanical property measured by non-destructive, high-speed and high-precision measurements can be obtained in qualitative and quantitative results. The developed high speed computation scheme is ready for applications where full-field mechanical properties are needed in a nondestructive and nearly real-time way.Keywords: guided waves, material characterization, nondestructive evaluation, parallel processing
Procedia PDF Downloads 202964 Swastika Shape Multiband Patch Antenna for Wireless Applications on Low Cost Substrate
Authors: Md. Samsuzzaman, M. T. Islam, J. S. Mandeep, N. Misran
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In this article, a compact simple structure modified Swastika shape patch multiband antenna on a substrate of available low cost polymer resin composite material is designed for Wi-Fi and WiMAX applications. The substrate material consists of an epoxy matrix reinforced by woven glass. The designed micro-strip line fed compact antenna comprises of a planar wide square slot ground with four slits and Swastika shape radiation patch with a rectangular slot. The effect of the different substrate materials on the reflection coefficients of the proposed antennas was also analyzed. It can be clearly seen that the proposed antenna provides a wider bandwidth and acceptable return loss value compared to other reported materials. The simulation results exhibits that the antenna has an impedance bandwidth with -10 dB return loss at 3.01-3.89 GHz and 4.88-6.10 GHz which can cover both the WLAN, WiMAX and public safety WLAN bands. The proposed swastika shape antenna was designed and analyzed by using a finite element method based simulator HFSS and designed on a low cost FR4 (polymer resin composite material) printed circuit board. The electrical performances and superior frequency characteristics make the proposed material antenna desirable for wireless communications.Keywords: epoxy resin polymer, multiband, swastika shaped, wide slot, WLAN/WiMAX
Procedia PDF Downloads 452963 The Display of Environmental Information to Promote Energy Saving Practices: Evidence from a Massive Behavioral Platform
Authors: T. Lazzarini, M. Imbiki, P. E. Sutter, G. Borragan
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While several strategies, such as the development of more efficient appliances, the financing of insulation programs or the rolling out of smart meters represent promising tools to reduce future energy consumption, their implementation relies on people’s decisions-actions. Likewise, engaging with consumers to reshape their behavior has shown to be another important way to reduce energy usage. For these reasons, integrating the human factor in the energy transition has become a major objective for researchers and policymakers. Digital education programs based on tangible and gamified user interfaces have become a new tool with potential effects to reduce energy consumption4. The B2020 program, developed by the firm “Économie d’Énergie SAS”, proposes a digital platform to encourage pro-environmental behavior change among employees and citizens. The platform integrates 160 eco-behaviors to help saving energy and water and reducing waste and CO2 emissions. A total of 13,146 citizens have used the tool so far to declare the range of eco-behaviors they adopt in their daily lives. The present work seeks to build on this database to identify the potential impact of adopted energy-saving behaviors (n=62) to reduce the use of energy in buildings. To this end, behaviors were classified into three categories regarding the nature of its implementation (Eco-habits: e.g., turning-off the light, Eco-actions: e.g., installing low carbon technology such as led light-bulbs and Home-Refurbishments: e.g., such as wall-insulation or double-glazed energy efficient windows). General Linear Models (GLM) disclosed the existence of a significantly higher frequency of Eco-habits when compared to the number of home-refurbishments realized by the platform users. While this might be explained in part by the high financial costs that are associated with home renovation works, it also contrasts with the up to three times larger energy-savings that can be accomplished by these means. Furthermore, multiple regression models failed to disclose the expected relationship between energy-savings and frequency of adopted eco behaviors, suggesting that energy-related practices are not necessarily driven by the correspondent energy-savings. Finally, our results also suggested that people adopting more Eco-habits and Eco-actions were more likely to engage in Home-Refurbishments. Altogether, these results fit well with a growing body of scientific research, showing that energy-related practices do not necessarily maximize utility, as postulated by traditional economic models, and suggest that other variables might be triggering them. Promoting home refurbishments could benefit from the adoption of complementary energy-saving habits and actions.Keywords: energy-saving behavior, human performance, behavioral change, energy efficiency
Procedia PDF Downloads 200962 Effect of BaO-Bi₂O₃-P₂O₅ Glass Additive on Structural and Dielectric Properties of BaTiO₃ Ceramics
Authors: El Mehdi Haily, Lahcen Bih, Mohammed Azrour, Bouchaib Manoun
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The effects of xBi₂O₃-yBaO-zP₂O₅ (BBP) glass addition on the sintering, structural, and dielectric properties of BaTiO₃ ceramic (BT) are studied. The BT ceramic was synthesized by the conventional solid-state reaction method while the glasses BaO-Bi₂O₃-P₂O₅ (BBP) were elaborated by melting and quenching process. Different composites BT-xBBP were formed by mixing the BBP glasses with BT ceramic. For each glass composition, where the ratio (x:y:z) is maintained constant, we have developed three composites with different glass weight percentage (x = 2.5, 5, and 7.5 wt %). Addition of the glass helps in better sintering at lower temperatures with the presence of liquid phase at the respective sintering temperatures. The results showed that the sintering temperature decreased from more than 1300°C to 900°C. Density measurements of the composites are performed using the standard Archimedean method with water as medium liquid. It is found that their density and molar volume decrease and increase with glass content, respectively. Raman spectroscopy is used to characterize their structural approach. This technique has allowed the identification of different structural units of phosphate and the characteristic vibration modes of the BT. The electrical properties of the composite samples are carried out by impedance spectroscopy in the frequency range of 10 Hz to 1 MHz under various temperatures from 300 to 473 K. The obtained results show that their dielectric properties depend both on the content of the glass in the composite and the Bi/P ratio in the glasses.Keywords: phosphate, glasses, composite, Raman spectroscopy, dielectric properties
Procedia PDF Downloads 163961 Fluorescence Quenching as an Efficient Tool for Sensing Application: Study on the Fluorescence Quenching of Naphthalimide Dye by Graphene Oxide
Authors: Sanaz Seraj, Shohre Rouhani
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Recently, graphene has gained much attention because of its unique optical, mechanical, electrical, and thermal properties. Graphene has been used as a key material in the technological applications in various areas such as sensors, drug delivery, super capacitors, transparent conductor, and solar cell. It has a superior quenching efficiency for various fluorophores. Based on these unique properties, the optical sensors with graphene materials as the energy acceptors have demonstrated great success in recent years. During quenching, the emission of a fluorophore is perturbed by a quencher which can be a substrate or biomolecule, and due to this phenomenon, fluorophore-quencher has been used for selective detection of target molecules. Among fluorescence dyes, 1,8-naphthalimide is well known for its typical intramolecular charge transfer (ICT) and photo-induced charge transfer (PET) fluorophore, strong absorption and emission in the visible region, high photo stability, and large Stokes shift. Derivatives of 1,8-naphthalimides have found applications in some areas, especially fluorescence sensors. Herein, the fluorescence quenching of graphene oxide has been carried out on a naphthalimide dye as a fluorescent probe model. The quenching ability of graphene oxide on naphthalimide dye was studied by UV-VIS and fluorescence spectroscopy. This study showed that graphene is an efficient quencher for fluorescent dyes. Therefore, it can be used as a suitable candidate sensing platform. To the best of our knowledge, studies on the quenching and absorption of naphthalimide dyes by graphene oxide are rare.Keywords: fluorescence, graphene oxide, naphthalimide dye, quenching
Procedia PDF Downloads 591