Search results for: minimum and maximum flows

Authors: Cuiyang Feng, Xu Tang, Yi Jin

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Coal is the most important primary energy source in China, which exerts a significant influence on the rapid economic growth. However, it makes the water resources to be a constraint on coal industry development, on account of the reverse geographical distribution between coal and water. To ease the pressure on water shortage, the ‘3 Red Lines’ water policies were announced by the Chinese government, and then ‘water for coal’ plan was added to that policies in 2013. This study utilized a structural path analysis (SPA) based on the multi-regional input-output table to quantify the virtual water flows caused by coal consumption in different stages. Results showed that the direct water input (the first stage) was the highest amount in all stages of coal consumption, accounting for approximately 30% of total virtual water content. Regional analysis demonstrated that virtual water trade alleviated the pressure on water use for coal consumption in water shortage areas, but the import of virtual water was not from the areas which are rich in water. Sectoral analysis indicated that the direct inputs from the sectors of ‘production and distribution of electric power and heat power’ and ‘Smelting and pressing of metals’ took up the major virtual water flows, while the sectors of ‘chemical industry’ and ‘manufacture of non-metallic mineral products’ importantly but indirectly consumed the water. With the population and economic growth in China, the water demand-and-supply gap in coal consumption would be more remarkable. In additional to water efficiency improvement measures, the central government should adjust the strategies of the virtual water trade to address local water scarcity issues. Water resource as the main constraints should be highly considered in coal policy to promote the sustainable development of the coal industry.

Keywords: coal consumption, multi-regional input-output model, structural path analysis, virtual water

Procedia PDF Downloads 282

Authors: Hasan Atakan Sengul, Nergis Canturk, Bahar Erbas

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Drinking water is indispensable for life. With increasing awareness of communities, the content of drinking water and tap water has been a matter of curiosity. The presence of Bisphenol-A is the top one when content curiosity is concerned. The most used chemical worldwide for production of polycarbonate plastics and epoxy resins is Bisphenol-A. People are exposed to Bisphenol-A chemical, which disrupts the endocrine system, almost every day. Each year it is manufactured an average of 5.4 billion kilograms of Bisphenol-A. Linear formula of Bisphenol-A is (CH₃)₂C(C₆H₄OH)₂, its molecular weight is 228.29 and CAS number is 80-05-7. Bisphenol-A is known to be used in the manufacturing of plastics, along with various chemicals. Bisphenol-A, an industrial chemical, is used in the raw materials of packaging mate-rials in the monomers of polycarbonate and epoxy resins. The pass through the nutrients of Bisphenol-A substance happens by packaging. This substance contaminates with nutrition and penetrates into body by consuming. International researches show that BPA is transported through body fluids, leading to hormonal disorders in animals. Experimental studies on animals report that BPA exposure also affects the gender of the newborn and its time to reach adolescence. The extent to what similar endocrine disrupting effects are on humans is a debate topic in many researches. In our country, detailed studies on BPA have not been done. However, it is observed that 'BPA-free' phrases are beginning to appear on plastic packaging such as baby products and water carboys. Accordingly, this situation increases the interest of the society about the subject; yet it causes information pollution. In our country, all national and international studies on exposure to BPA have been examined and Ankara province has been designated as testing region. To assess the effects of plastic use in daily habits of people and the plastic amounts removed out of the body, the results of the survey conducted with volunteers who live in Ankara has been analyzed with Sciex appliance by means of LC-MS/MS in the laboratory and the amount of exposure and BPA removal have been detected by comparing the results elicited before. The results have been compared with similar studies done in international arena and the relation between them has been exhibited. Consequently, there has been found no linear correlation between the amount of BPA in drinking water and the amount of BPA in urine. This has also revealed that environmental exposure and the habits of daily plastic use have also direct effects a human body. When the amount of BPA in drinking water is considered; minimum 0.028 µg/L, maximum 1.136 µg/L, mean 0.29194 µg/L and SD(standard deviation)= 0.199 have been detected. When the amount of BPA in urine is considered; minimum 0.028 µg/L, maximum 0.48 µg/L, mean 0.19181 µg/L and SD= 0.099 have been detected. In conclusion, there has been found no linear correlation between the amount of BPA in drinking water and the amount of BPA in urine (r= -0.151). The p value of the comparison between drinking water’s and urine’s BPA amounts is 0.004 which shows that there is a significant change and the amounts of BPA in urine is dependent on the amounts in drinking waters (p < 0.05). This has revealed that environmental exposure and daily plastic habits have also direct effects on the human body.

Keywords: analyze of bisphenol-A, BPA, BPA in drinking water, BPA in urine

Procedia PDF Downloads 109

Authors: Haitham A. Hussein, Rozi Abdullah, Issa Saket, Md. Azlin

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The gravitational effect has been extensively applied to separate oil from water in water and wastewater treatment systems. The maximum oil globules removal efficiency is improved by obtaining the best flow uniformity in separator tanks. This study used 2D computational fluid dynamics (CFD) to investigate the effect of different inlet baffle positions inside the separator tank. Laboratory experiment has been conducted, and the measured velocity fields which were by Nortek Acoustic Doppler Velocimeter (ADV) are used to verify the CFD model. Computational investigation results indicated that the construction of an inlet baffle in a suitable location provides the minimum recirculation zone volume, creates the best flow uniformity, and dissipates kinetic energy in the oil and water separator tank. Useful formulas were predicted to design the oil and water separator tanks geometry based on an experimental model.

Keywords: oil/water separator tanks, inlet baffles, CFD, VOF

Procedia PDF Downloads 333

Authors: Qurrat Ul Ain Farooq, Misha Arshad, Malik Abid Mehmood

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The experiment under discussion was carried out to check the effect of different concentrations of sucrose (2%, 4%, 6%), CuSO4 (200ppm, 300ppm, 400 ppm), GA3 (25ppm, 50ppm, 75 ppm), and combinations of sucrose and GA3 (2% +25 ppm), (4%+50 ppm), (6%+75 ppm) on the carnation cut flower. Visual symptoms of flower senescence, changes in weight (g) of a flower was observed and recorded by using weight balance. The experiment was laid out according to CRD (Complete Randomized Design) it was two-factor factorial, the software used for the analysis was Statistix. Maximum TSS were found in 6% sucrose + 75 ppm GA3 (8.3 %) followed by CuSO4 400 ppm, 4% sucrose + 50 ppm GA3 and 6% sucrose + 75 ppm GA3. Maximum vase life in term of days was recorded in treatment. CuSO4 400 ppm and 6% sucrose + 75 ppm GA3 (8 days) followed by CuSO4 200 ppm (7.7 days). CuSO4 300 ppm & 6% sucrose + 75 ppm GA3 were at par (7 days). Maximum water uptake was also observed in 6% sucrose + 75 ppm GA3 (56.7 ml) followed by CuSO4 400 ppm (49.7 ml) and 50 ppm GA3 (45 ml). Hence, CuSO4 400 ppm found best in all aspects.

Keywords: carnation, vaselife, GA3, CuSO4, sucrose

Procedia PDF Downloads 324

Authors: Zhiqiang Cheng, Qingliang He, Lu Li, Jie Ren

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The safety of pipelines in the condition of frost heave or thaw settlement is necessarily evaluated. A full-scale experiment pipe with the typical structure configuration in station pipeline is constructed, the residual stress is tested with X-ray residual stress device, and the residual stress field of pipe is analyzed. The evolution of pipe strain with pressure in the scope of maximum allowable operation pressure (MAOP) is investigated by both strain gauge and X-ray methods. Load caused by frost heave or thaw settlement is simulated by two ways of lifting jack. The relation of maximum stress of pipe and clearances between supporter and pipe is studied in case of frost heave. The relation of maximum stress of pipe and maximum deformation of pipe on the ground is studied in case of thaw settlement. The study methods and results are valuable for safety assessment of station pipeline according to clearances or deformation in the condition of frost heave or thaw settlement.

Keywords: frost heave, pipeline, stress analysis, thaw settlement

Procedia PDF Downloads 163

Authors: Ping Tan, Xiaomeng Su, Yi Shen

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The motion intention in the motor imagery braincomputer interface is identified by classifying the event-related desynchronization (ERD) and event-related synchronization ERS characteristics of sensorimotor rhythm (SMR) in EEG signals. When the subject imagines different limbs or different parts moving, the rhythm components and bandwidth will change, which varies from person to person. How to find the effective sensorimotor frequency band of subjects is directly related to the classification accuracy of brain-computer interface. To solve this problem, this paper proposes a Minimum Distance to Riemannian Mean Classification method based on Non-Uniform Filter Banks. During the training phase, the EEG signals are decomposed into multiple different bandwidt signals by using multiple band-pass filters firstly; Then the spatial covariance characteristics of each frequency band signal are computered to be as the feature vectors. these feature vectors will be classified by the MDRM (Minimum Distance to Riemannian Mean) method, and cross validation is employed to obtain the effective sensorimotor frequency bands. During the test phase, the test signals are filtered by the bandpass filter of the effective sensorimotor frequency bands, and the extracted spatial covariance feature vectors will be classified by using the MDRM. Experiments on the BCI competition IV 2a dataset show that the proposed method is superior to other classification methods.

Keywords: non-uniform filter banks, motor imagery, brain-computer interface, minimum distance to Riemannian mean

Procedia PDF Downloads 89

Authors: Sungchul Ha, Hyunwoo Kim

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In mobile ad hoc networks, all nodes in a network only have limited resources and calculation ability. Therefore communication topology which have long lifetime is good for all nodes in mobile ad hoc networks. There are a variety of researches on security problems in wireless ad hoc networks. The existing many researches try to make efficient security schemes to reduce network power consumption and enhance network lifetime. Because a new node can join the network at any time, the wireless ad hoc networks are exposed to various threats and can be destroyed by attacks. Resource consumption is absolutely necessary to secure networks, but more resource consumption can be a critical problem to network lifetime. This paper focuses on efficient monitoring node distribution to enhance network lifetime in wireless ad hoc networks. Since the wireless ad hoc networks cannot use centralized infrastructure and security systems of wired networks, a new special IDS scheme is necessary. The scheme should not only cover all nodes in a network but also enhance the network lifetime. In this paper, we propose an efficient IDS node distribution scheme using minimum spanning tree (MST) method. The simulation results show that the proposed algorithm has superior performance in comparison with existing algorithms.

Keywords: MANETs, IDS, power control, minimum spanning tree

Procedia PDF Downloads 342

Authors: Mohammad Reza Ebrahimi, Behnaz Mahdaviani

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Increasing renewable sources such photovoltaic are the reason of environmental pollution. Because photovoltaic generates power in low voltage, first, generated power should increase. Usually, distributed generation injects their power to AC-Grid, hence after voltage increasing an inverter is needed to convert DC power to AC power. This results in utilization two series converter that grows cost, complexity, and low efficiency. In this paper a single stage inverter is utilized to boost and invert in one stage. Control of this scheme is easier, and its initial cost decreases comparing to conventional double stage inverters. A simple control scheme is used to control active power as well as minimum total harmonic distortion (THD) in injected current. Simulations in MATLAB demonstrate better outputs comparing with conventional approaches.

Keywords: maximum power point tracking, boost inverter, control strategy, three phase inverter

Procedia PDF Downloads 345

Authors: H. M. Mobarak, Helen Wu, Chunhui Yang

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In this study, an analytical model is developed to study crack breathing behavior under the effect of crack location and unbalance force. Crack breathing behavior is determined using effectual bending angle by studying the transient change in closed area of the crack. The status of the crack of a balanced shaft is symmetrical about shaft rotational angle and the duration of each crack status remains unchanged. The global stiffness of the balanced shaft is independent of crack location. Different crack breathing behavior for the unbalanced shaft has been observed. The influence of crack location on the unbalanced shaft stiffness can be divided into three regions. When the crack is located between 0.3L and 0.8335L, where L is the total length of the shaft, the unbalanced shaft is less stiff and when located outside this region it is stiffer than the balanced shaft. It was also found that unbalanced shaft stiffness has a maximum value with a crack at 0.1946L, a minimum value at 0.8053L and same value as balanced shaft at 0.3L and 0.8335L.

Keywords: cracked shaft, crack location, shaft stiffness, unbalanced force

Procedia PDF Downloads 284

Authors: Hela Ayeb Mrabtini, Ghazi Bellakhal, Jamel Chahed

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The presence of the dispersed phase in gas-liquid bubbly flow considerably alters the liquid turbulence. The bubbles induce turbulent fluctuations that enhance the global liquid turbulence level and alter the mechanisms of turbulence. RANS modeling of uniformly sheared flows on an isolated sphere centered in a control volume is performed using first and second order turbulence closures. The sphere is placed in the production-dissipation equilibrium zone where the liquid velocity is set equal to the relative velocity of the bubbles. The void fraction is determined by the ratio between the sphere volume and the control volume. The analysis of the turbulence statistics on the control volume provides numerical results that are interpreted with regard to the effect of the bubbles wakes on the turbulence structure in uniformly sheared bubbly flow. We assumed for this purpose that at low void fraction where there is no hydrodynamic interaction between the bubbles, the single-phase flow simulation on an isolated sphere is representative on statistical average of a sphere network. The numerical simulations were firstly validated against the experimental data of bubbly homogeneous turbulence with constant shear and then extended to produce numerical results for a wide range of shear rates from 0 to 10 s^-1. These results are compared with our turbulence closure proposed for gas-liquid bubbly flows. In this closure, the turbulent stress tensor in the liquid is split into a turbulent dissipative part produced by the gradient of the mean velocity which also contains the turbulence generated in the bubble wakes and a pseudo-turbulent non-dissipative part induced by the bubbles displacements. Each part is determined by a specific transport equation. The simulations of uniformly sheared flows on an isolated sphere reproduce the mechanisms related to the turbulent part, and the numerical results are in perfect accordance with the modeling of the transport equation of the turbulent part. The reduction of second order turbulence closure provides a description of the modification of turbulence structure by the bubbles presence using a dimensionless number expressed in terms of two-time scales characterizing the turbulence induced by the shear and that induced by bubbles displacements. The numerical simulations carried out in the framework of a comprehensive analysis reproduce particularly the attenuation of the turbulent friction showed in the experimental results of bubbly homogeneous turbulence subjected to a constant shear.

Keywords: gas-liquid bubbly flows, homogeneous turbulence, turbulence closure, uniform shear

Procedia PDF Downloads 439

Authors: Yunhui Sun, Qingquan Liu, Xiaoliang Wang

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Dense granular flows widely exist in geological flows such as debris flow, landslide, or sheet flow, where both the interparticle and solid-liquid interactions are important to modify the flow. So, a two-phase approach with both phases correctly modelled is important for a better investigation of the saturated granular flows. However, a proper closure model covering a wide range of flowing states for the solid phase is still lacking. This study first employs a chute flow experiment based on the refractive index matching method, which makes it possible to obtain internal flow information such as velocity, shear rate, granular fluctuation, and volume fraction. The granular stress is obtained based on a steady assumption. The kinetic theory is found to describe the stress dependence on the flow state well. More importantly, the granular rheology is found to be frictionally dominated under weak shear and collisionally dominated under strong shear. The results presented thus provide direct experimental evidence on a possible frictional-collisional closure model for the granular phase. The data indicates that both frictional stresses exist over a wide range of the volume fraction, though traditional theory believes it vanishes below a critical volume fraction. Based on the findings, a two-phase model is used to simulate the chute flow. Both phases are modelled as continuum media, and the inter-phase interactions, such as drag force and pressure gradient force, are considered. The frictional-collisional model is used for the closure of the solid phase stress. The profiles of the kinematic properties agree well with the experiments. This model is further used to simulate immersed granular collapse, which is unsteady in nature, to study the applicability of this model, which is derived from steady flow.

Keywords: closure model, collision, friction, granular flow, two-phase model

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Authors: Min Kyung An, Hyuk Cho

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In this paper, we study the Minimum Latency Broadcast Scheduling (MLBS) problem in wireless sensor networks (WSNs). The main issue of the MLBS problem is to compute schedules with the minimum number of timeslots such that a base station can broadcast data to all other sensor nodes with no collisions. Unlike existing works that utilize the traditional omni-directional WSNs, we target the directional WSNs where nodes can collaboratively determine and orientate their antenna directions. We first develop a 7-approximation algorithm, adopting directional WSNs. Our ratio is currently the best, to the best of our knowledge. We then validate the performance of the proposed algorithm through simulation.

Keywords: broadcast, collision-free, directional antenna, approximation, wireless sensor networks

Procedia PDF Downloads 319

Authors: Ziyu Diao, Yanyan Zhang, Zhentao Liu, Ruidong Yan

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The update frequency of wear profile in main bearing wear prognosis of internal combustion engine plays an important role in the calculation efficiency and accuracy. In order to investigate the appropriate cycle index of the simplified working condition of wear simulation, the main bearing-crankshaft journal friction pair of a diesel engine in service was studied in this paper. The method of multi-body dynamics simulation was used, and the wear prognosis model of the main bearing was established. Several groups of cycle indexes were set up for the wear calculation, and the maximum wear depth and wear profile were compared and analyzed. The results showed that when the cycle index reaches 3, the maximum deviation rate of the maximum wear depth is about 2.8%, and the maximum deviation rate comes to 1.6% when the cycle index reaches 5. This study provides guidance and suggestions for the optimization of wear prognosis by selecting appropriate value of cycle index according to the requirement of calculation cost and accuracy of the simulation work.

Keywords: cycle index, deviation rate, wear calculation, wear profile

Procedia PDF Downloads 139

Authors: Ali Aghazadegan, Ali Shokria, Julia Mullarneya, Jon Tunnicliffe

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River channel confluences are dynamic systems with branching structures that exhibit a high degree of complexity both in natural and man-made open channel networks. Recent and past fields and modeling have investigated the river dynamics modeling of confluent based on a series of over-simplified assumptions (i.e. straight tributary channel with a bend with a 90° junction angle). Accurate assessment of such systems is important to the design and management of hydraulic structures and river engineering processes. Despite their importance, there has been little study of the hydrodynamics characteristics of river confluences, and the link between flow hydrodynamics and confluence morphodynamics in the confluence is still incompletely understood. This paper studies flow structures in confluences, morphodynamics and deposition patterns in 30 and 90 degrees confluences with different flow conditions. The results show that the junction angle is primarily the key factor for the determination of the confluence bed morphology and sediment pattern, while the discharge ratio is a secondary factor. It also shows that super elevation created by mixing flows is a key function of the morphodynamics patterns.

Keywords: helical flow, river confluence, bed morphology , secondary flows, shear layer

Procedia PDF Downloads 118

Authors: Mamidi Ramakrishna Rao

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Doubly-fed induction generator (DFIG) is currently the choice for many wind turbines. These generators, when connected to the grid through a converter, is subjected to varied power system conditions like voltage variation, frequency variation, short circuit fault conditions, etc. Further, many countries like Canada, Germany, UK, Scotland, etc. have distinct grid codes relating to wind turbines. Accordingly, following the network faults, wind turbines have to supply a definite reactive current. To satisfy the requirements including reactive current capability, an optimum electrical design becomes a mandate for DFIG to function. This paper intends to optimize the equivalent circuit parameters of an electrical design for satisfactory DFIG performance. Direct search method has been used for optimization of the parameters. The variables selected include electromagnetic core dimensions (diameters and stack length), slot dimensions, radial air gap between stator and rotor and winding copper cross section area. Optimization for 2 MW DFIG has been executed separately for three objective functions - maximum reactive power capability (Case I), maximum efficiency (Case II) and minimum weight (Case III). In the optimization analysis program, voltage variations (10%), power factor- leading and lagging (0.95), speeds for corresponding to slips (-0.3 to +0.3) have been considered. The optimum designs obtained for objective functions were compared. It can be concluded that direct search method of optimization helps in determining an optimum electrical design for each objective function like efficiency or reactive power capability or weight minimization.

Keywords: direct search, DFIG, equivalent circuit parameters, optimization

Procedia PDF Downloads 233

Authors: Temesgen Sidamo, Prakruti S. Rao, Eleni Akllilu, Workineh Shibeshi, Yumi Park, Yong-Soon Cho, Jae-Gook Shin, Scott K. Heysell, Stellah G. Mpagama, Ephrem Engidawork

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The fluoroquinolones (FQs) are used off-label for the treatment of multidrug-resistant tuberculosis (MDR-TB), and for evaluation in shortening the duration of drug-susceptible TB in recently prioritized regimens. Within the class, levofloxacin (LFX) and moxifloxacin (MXF) play a substantial role in ensuring success in treatment outcomes. However, sub-therapeutic plasma concentrations of either LFX or MXF may drive unfavorable treatment outcomes. To the best of our knowledge, the pharmacokinetics of LFX and MXF in Ethiopian patients with MDR-TB have not yet been investigated. Therefore, the aim of this study was to develop a population pharmacokinetic (PopPK) model of levofloxacin (LFX) and moxifloxacin (MXF) and assess the percent probability of target attainment (PTA) as defined by the ratio of the area under the plasma concentration-time curve over 24-h (AUC0-24) and the in vitro minimum inhibitory concentration (MIC) (AUC0-24/MIC) in Ethiopian MDR-TB patients. Steady-state plasma was collected from 39 MDR-TB patients enrolled in the programmatic treatment course and the drug concentrations were determined using optimized liquid chromatography-tandem mass spectrometry. In addition, the in vitro MIC of the patients' pretreatment clinical isolates was determined. PopPK and simulations were run at various doses, and PK parameters were estimated. The effect of covariates on the PK parameters and the PTA for maximum mycobacterial kill and resistance prevention was also investigated. LFX and MXF both fit in a one-compartment model with adjustments. The apparent volume of distribution (V) and clearance (CL) of LFX were influenced by serum creatinine (Scr), whereas the absorption constant (Ka) and V of MXF were influenced by Scr and BMI, respectively. The PTA for LFX maximal mycobacterial kill at the critical MIC of 0.5 mg/L was 29%, 62%, and 95% with the simulated 750 mg, 1000 mg, and 1500 mg doses, respectively, whereas the PTA for resistance prevention at 1500 mg was only 4.8%, with none of the lower doses achieving this target. At the critical MIC of 0.25 mg/L, there was no difference in the PTA (94.4%) for maximum bacterial kill among the simulated doses of MXF (600 mg, 800 mg, and 1000 mg), but the PTA for resistance prevention improved proportionately with dose. Standard LFX and MXF doses may not provide adequate drug exposure. LFX PopPK is more predictable for maximum mycobacterial kill, whereas MXF's resistance prevention target increases with dose. Scr and BMI are likely to be important covariates in dose optimization or therapeutic drug monitoring (TDM) studies in Ethiopian patients.

Keywords: population PK, PTA, moxifloxacin, levofloxacin, MDR-TB patients, ethiopia

Procedia PDF Downloads 92

Authors: Yogita Mishra, Arijit Roy, Dhruval Bhavsar

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The study estimates the nitrogen concentration in selected vegetation community’s i.e. chir pine (pinusroxburghii) by using hyperspectral satellite data and also identified the appropriate spectral bands and nitrogen indices. The Short Wave InfraRed reflectance spectrum at 1790 nm and 1680 nm shows the maximum possible absorption by nitrogen in selected species. Among the nitrogen indices, log normalized nitrogen index performed positively and negatively too. The strong positive correlation is taken out from 1510 nm and 760 nm for the pinusroxburghii for leaf nitrogen concentration and leaf nitrogen mass while using NDNI. The regression value of R² developed by using linear equation achieved maximum at 0.7525 for the analysis of satellite image data and R² is maximum at 0.547 for ground truth data for pinusroxburghii respectively.

Keywords: hyperspectral, NDNI, nitrogen concentration, regression value

Procedia PDF Downloads 268

Authors: Khalil Aghapouramin

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The aim of the present work is to investigate the mechanical and microstructural properties of dissimilar and similar aluminum alloys welded by Friction Stir Welding (FSW). The specimens investigated by applying different welding speed and rotary speed. Typically, mechanical properties of the joints performed through tensile test fatigue test and microhardness (HV) at room temperature. Fatigue test investigated by using electromechanical testing machine under constant loading control with similar since wave loading. The Maximum stress versus minimum got the range between 0.1 to 0.3 in the research. Based upon welding parameters by optical observation and scanning electron microscopy microstructural properties fulfilled with a cross section of welds, in addition, SEM observations were made of the fracture surfaces

Keywords: friction stir welding, fatigue and tensile test, Al alloys, microstructural behavior

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Authors: Redhouane Ghernaout, Amira Fredj, Boualem Remini

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Suspended sediment transport is a serious problem worldwide, but it is much more worrying in certain regions of the world, as is the case in the Maghreb and more particularly in Algeria. It continues to take disturbing proportions in Northern Algeria due to the variability of rains in time and in space and constant deterioration of vegetation. Its prediction is essential in order to identify its intensity and define the necessary actions for its reduction. The purpose of this study is to analyze the concentration data of suspended sediment measured at Wadi El-Abtal Hydrometric Station. It also aims to find and highlight regressive power relationships, which can explain the suspended solid flow by the measured liquid flow. The study strives to find models of artificial neural networks linking the flow, month and precipitation parameters with solid flow. The obtained results show that the power function of the solid transport rating curve and the models of artificial neural networks are appropriate methods for analysing and estimating suspended sediment transport in Wadi Mina at Wadi El-Abtal Hydrometric Station. They made it possible to identify in a fairly conclusive manner the model of neural networks with four input parameters: the liquid flow Q, the month and the daily precipitation measured at the representative stations (Frenda 013002 and Ain El-Hadid 013004 ) of the watershed. The model thus obtained makes it possible to estimate the daily solid flows (interpolate and extrapolate) even beyond the period of observation of solid flows (1985/86 to 1999/00), given the availability of the average daily liquid flows and daily precipitation since 1953/1954.

Keywords: suspended sediment, concentration, regression, liquid flow, solid flow, artificial neural network, modeling, mina, algeria

Procedia PDF Downloads 74

Authors: Jose Daniel Hoyos Giraldo, Jesus Hernan Jimenez Giraldo, Juan Pablo Alvarado Perilla

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Range and endurance are the main limitations of electric aircraft due to the nature of its source of power. The improvement of efficiency on this kind of systems is extremely meaningful to encourage the aircraft operation with less environmental impact. The propeller efficiency highly affects the overall efficiency of the propulsion system; hence its optimization can have an outstanding effect on the aircraft performance. An optimization method is applied to an aircraft propeller in order to maximize its range and endurance by estimating the best combination of geometrical parameters such as diameter and airfoil, chord and pitch distribution for a specific aircraft design at a certain cruise speed, then the rotational speed at which the propeller operates at minimum current consumption is estimated. The optimization is based on the Blade Element Momentum (BEM) method, additionally corrected to account for tip and hub losses, Mach number and rotational effects; furthermore an airfoil lift and drag coefficients approximation is implemented from Computational Fluid Dynamics (CFD) simulations supported by preliminary studies of grid independence and suitability of different turbulence models, to feed the BEM method, with the aim of achieve more reliable results. Additionally, Vortex Theory is employed to find the optimum pitch and chord distribution to achieve a minimum induced loss propeller design. Moreover, the optimization takes into account the well-known brushless motor model, thrust constraints for take-off runway limitations, maximum allowable propeller diameter due to aircraft height and maximum motor power. The BEM-CFD method is validated by comparing its predictions for a known APC propeller with both available experimental tests and APC reported performance curves which are based on Vortex Theory fed with the NASA Transonic Airfoil code, showing a adequate fitting with experimental data even more than reported APC data. Optimal propeller predictions are validated by wind tunnel tests, CFD propeller simulations and a study of how the propeller will perform if it replaces the one of on known aircraft. Some tendency charts relating a wide range of parameters such as diameter, voltage, pitch, rotational speed, current, propeller and electric efficiencies are obtained and discussed. The implementation of CFD tools shows an improvement in the accuracy of BEM predictions. Results also showed how a propeller has higher efficiency peaks when it operates at high rotational speed due to the higher Reynolds at which airfoils present lower drag. On the other hand, the behavior of the current consumption related to the propulsive efficiency shows counterintuitive results, the best range and endurance is not necessary achieved in an efficiency peak.

Keywords: BEM, blade design, CFD, electric aircraft, endurance, optimization, range

Procedia PDF Downloads 86

Authors: Mahpara Pirzada, Mansoor Ali Shah, Saima Pthan, Kamal Khan, Faiza

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Present study based on biodiversity of aphid in different crops of Hyderabad district and its, surrounding area to observe the biodiversity of aphids, host plant range of the aphids in Hyderabad and their population also infestation and yield loss aphid on different crops. We have surveyed different fields of Hyderabad, Jamshoro, and collected the aphids from various parts of plants, grasses, and herb with the help of camel brush. They have been brought to the laboratory into plastic jars and preserved in Glycerin (Glycerol). As a result, 383 individuals belonging to 3 species were identified. These identified species were Aphis fabae, Myzus persicae, and Brevicoryne brassicae. Out of the 3 habitats the maximum richness, evenness, and diversity were recorded in agriculture crops followed by flowering vegetables and minimum in fodder crops. The most abundant specie is Myzus persicae.

Keywords: aphid species, biodiversity, Homoptera:Aphididae, Pakistan

Procedia PDF Downloads 297

Authors: M. K. Dce

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The aim of this paper is to investigate the behavior of simply supported beams having rectangular section and subjected to uniformly distributed load (UDL). In this study five beams of span 5m, 6m, 7m and 8m have been considered. The width of all the beams is 400 mm and span to depth ratio has been taken as 12. The superimposed live load has been increased from 10 kN/m to 25 kN/m at the interval of 5 kN/m. The analysis of the beams has been carried out using the elastic beam theory. On the basis of present study it has been concluded that the maximum bending moment as well as deflection occurs at the mid-span of simply supported beam and its magnitude increases in proportion to magnitude of UDL. Moreover, the study suggests that the maximum moment is proportional to square of span and maximum deflection is proportional to fourth power of span.

Keywords: beam, UDL, bending moment, deflection, elastic beam theory

Procedia PDF Downloads 368

Authors: Dia I. Abu-Al-Nadi, M. J. Mismar, T. H. Ismail

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A technique for estimating the direction-of-arrival (DOA) of unknown number of source signals is presented using the eigen-approach. The eigenvector corresponding to the minimum eigenvalue of the autocorrelation matrix yields the minimum output power of the array. Also, the array polynomial with this eigenvector possesses roots on the unit circle. Therefore, the pseudo-spectrum is found by perturbing the phases of the roots one by one and calculating the corresponding array output power. The results indicate that the DOAs and the number of source signals are estimated accurately in the presence of a wide range of input noise levels.

Keywords: array signal processing, direction-of-arrival, antenna arrays, Eigenvalues, Eigenvectors, Lagrange multiplier

Procedia PDF Downloads 311

Authors: Li Chen

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For an aerofoil or hydrofoil in high Reynolds number flows, broadband noise is generated efficiently as the result of the turbulence convecting over the trailing edge. This noise can be related to the surface pressure fluctuations, which can be predicted by either CFD or empirical models. However, in reality, the aerofoil or hydrofoil often operates at an angle of attack. Under this situation, the flow is subjected to an Adverse-Pressure-Gradient (APG), and as a result, a flow separation may occur. This study is to assess trailing-edge noise models for such flows. In the present work, the trailing-edge noise from a 2D airfoil at 6 degree of angle of attach is investigated. Under this condition, the flow is experiencing a strong APG, and the flow separation occurs. The flow over the airfoil with a chord of 300 mm, equivalent to a Reynold Number 4x10⁵, is simulated using RANS with the SST k-ɛ turbulent model. The predicted surface pressure fluctuations are compared with the published experimental data and empirical models, and show a good agreement with the experimental data. The effect of the APG on the trailing edge noise is discussed, and the associated trailing edge noise is calculated.

Keywords: aero-acoustics, adverse-pressure gradient, computational fluid dynamics, trailing-edge noise

Procedia PDF Downloads 311

Authors: Zhao Weijie, Lin Xinjian, Liu Xiaojuan, Li Lihua

Abstract:

The Howland current pump is widely used in bio-impedance measurement. Much attention has been focused on the output impedance of the Howland circuit. Here we focus on the maximum load of the Howland source and discuss the relationship between the circuit parameters at maximum load. We conclude that the signal input terminal of the feedback resistor should be as large as possible, but that the current-limiting resistor should be smaller. The op-amp saturation voltage should also be high. The bandwidth of the circuit is proportional to the bandwidth of the op-amp. The Howland current pump was simulated using multisim12. When the AD8066AR was selected as the op-amp, the maximum load was 11.5 kΩ, and the Howland current pump had a stable output ipp to 2mAp up to 200 kHz. However, with an OPA847 op-amp and a load of 6.3 kΩ, the output current was also stable, and the frequency was as high as 3 MHz.

Keywords: bio-impedance, improved Howland current pump, load characteristics, bioengineering

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Authors: Radoslaw Pytlak, Damian Suski

Abstract:

The aim of the paper is to provide a computational tool for planning a haemodialysis process. It is shown that optimization methods can be used to obtain the most effective treatment focused on removing both urea and phosphorus during the process. In order to achieve that, the IV–compartment model of phosphorus kinetics is applied. This kinetics model takes into account a rebound phenomenon that can occur during haemodialysis and results in a hybrid model of the process. Furthermore, vector fields associated with the model equations are such that it is very likely that using the most intuitive objective functions in the planning problem could lead to solutions which include sliding motions. Therefore, building computational tools for solving the problem of planning a haemodialysis process has required constructing numerical algorithms for solving optimal control problems with hybrid systems. The paper concentrates on minimum time control of hybrid systems since this control objective is the most suitable for the haemodialysis process considered in the paper. The presented approach to optimal control problems with hybrid systems is different from the others in several aspects. First of all, it is assumed that a hybrid system can exhibit sliding modes. Secondly, the system’s motion on the switching surface is described by index 2 differential–algebraic equations, and that guarantees accurate tracking of the sliding motion surface. Thirdly, the gradients of the problem’s functionals are evaluated with the help of adjoint equations. The adjoint equations presented in the paper take into account sliding motion and exhibit jump conditions at transition times. The optimality conditions in the form of the weak maximum principle for optimal control problems with hybrid systems exhibiting sliding modes and with piecewise constant controls are stated. The presented sensitivity analysis can be used to construct globally convergent algorithms for solving considered problems. The paper presents numerical results of solving the haemodialysis planning problem.

Keywords: haemodialysis planning process, hybrid systems, optimal control, sliding motion

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Authors: X. Wang, T. J. Craft, H. Iacovides

Abstract:

When handling the near-wall regions of turbulent flows, it is necessary to account for the viscous effects which are important over the thin near-wall layers. Low-Reynolds- number turbulence models do this by including explicit viscous and also damping terms which become active in the near-wall regions, and using very fine near-wall grids to properly resolve the steep gradients present. In order to overcome the cost associated with the low-Re turbulence models, a more advanced wall function approach has been implemented within OpenFoam and tested together with a standard log-law based wall function in the prediction of flows which involve 2-D shock wave/turbulent boundary layer interactions (SWTBLIs). On the whole, from the calculation of the impinging shock interaction, the three turbulence modelling strategies, the Lauder-Sharma k-ε model with Yap correction (LS), the high-Re k-ε model with standard wall function (SWF) and analytical wall function (AWF), display good predictions of wall-pressure. However, the SWF approach tends to underestimate the tendency of the flow to separate as a result of the SWTBLI. The analytical wall function, on the other hand, is able to reproduce the shock-induced flow separation and returns predictions similar to those of the low-Re model, using a much coarser mesh.

Keywords: SWTBLIs, skin-friction, turbulence modeling, wall function

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Authors: M. K. Sheikh, Y. M. Laghari., P. K. Lashari., N. T. Narejo

Abstract:

The Indus River is one of the longest important rivers of the world in Asia that flows southward through Pakistan, merges into the Arabian Sea near the port city of Karachi in Sindh Province, and forms the Indus Delta. Fish are an important resource for humans worldwide, especially as food. In fish, healthy nutriments are present which are not found in any other meat source because it have a huge quantity of omega- 3 fatty acids, which are very essential for the human body. Ichthyologic surveys were conducted to explore the diversity of freshwater fishes, distribution, abundance and current status of the fishes at different spatial scale of the downstream, Indus River. Total eight stations were selected namely Railo Miyan (RM), Karokho (Kk), Khanpur (Kp), Mullakatiyar (Mk), Wasi Malook Shah (WMS), Branch Morie (BM), Sujawal (Sj) and Jangseer (JS). The study was carried in the period of January 2016 to December 2019 to identify River and biodiversity threats and to suggest recommendations for conservation. The data were analysed by different population diversity index. Altogether, 124 species were recorded belonging to 12 Orders and 43 Families from the downstream of Indus River. Among 124 species, 29% belong to high commercial value and 35% were trash fishes. 31% of fishes were identified as marine/estuarine origin (migratory) and 05% were exotic fish species. Perciformes is the most predominated order, contributing to 41% of families. Among 43 families, the family Cyprinidae was the richest family from all localities of downstream, represented by 24% of fish species demonstrating a significant dominance in the number of species. A significant difference was observed for species abundance in between all sites, the maximum abundance species were found at first location RM having 115 species and minimum observed at the last station JS 56 genera. In the recorded Ichthyofauna, seven groups were found according to the International Union for Conservation of Nature status (IUCN), where a high species ratio was collected, in Least Concern (LC) having 94 species, 11 were found as not evaluated (NE), whereas 8 was identified as near threatened (NT), 1 was recorded as critically endangered (CR), 11 were collected as data deficient (DD), and while 8 was observed as vulnerable (VU) and 3 endangered (EN) species. Different diversity index has been used extensively in environmental studies to estimate the species richness and abundance of ecosystems outputs of their wellness; a positive environment (biodiversity rich) with species at RM had an environmental wellness and biodiversity levels of 4.566% while a negative control environment (biodiversity poor) on last station JS had an environmental wellness and biodiversity levels of 3.931%. The status of fish biodiversity and river has been found under serious threat. Due to the lower diversity of fishes, it became not only venerable for fish but also risky for fishermen. Necessary steps are recommended to protect the biodiversity by conducting further conservative research in this area.

Keywords: ichthyofaunal biodiversity, threatened species, diversity index, Indus River downstream

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Authors: Kavian Khosravinia, Mohd Khair Hassan, Ribhan Zafira Abdul Rahman, Syed Abdul Rahman Al-Haddad

Abstract:

The CAN (controller area network) bus is introduced as a multi-master, message broadcast system. The messages sent on the CAN are used to communicate state information, referred as a signal between different ECUs, which provides data consistency in every node of the system. OBD-II Dongles that are based on request and response method is the wide-spread solution for extracting sensor data from cars among researchers. Unfortunately, most of the past researches do not consider resolution and quantity of their input data extracted through OBD-II technology. The maximum feasible scan rate is only 9 queries per second which provide 8 data points per second with using ELM327 as well-known OBD-II dongle. This study aims to develop and design a programmable, and latency-sensitive vehicle data acquisition system that improves the modularity and flexibility to extract exact, trustworthy, and fresh car sensor data with higher frequency rates. Furthermore, the researcher must break apart, thoroughly inspect, and observe the internal network of the vehicle, which may cause severe damages to the expensive ECUs of the vehicle due to intrinsic vulnerabilities of the CAN bus during initial research. Desired sensors data were collected from various vehicles utilizing Raspberry Pi3 as computing and processing unit with using OBD (request-response) and direct CAN method at the same time. Two types of data were collected for this study. The first, CAN bus frame data that illustrates data collected for each line of hex data sent from an ECU and the second type is the OBD data that represents some limited data that is requested from ECU under standard condition. The proposed system is reconfigurable, human-readable and multi-task telematics device that can be fitted into any vehicle with minimum effort and minimum time lag in the data extraction process. The standard operational procedure experimental vehicle network test bench is developed and can be used for future vehicle network testing experiment.

Keywords: CAN bus, OBD-II, vehicle data acquisition, connected cars, telemetry, Raspberry Pi3

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Authors: Dadash Huseynov, Elmira Aliyeva, Robert Hoogendoorn, Salomon Kroonenberg

Abstract:

The study of organic material in bottom sediments together with lithologic and biostratigraphic data improves our understanding of the evolution of fluvial and deltaic systems. The modern Kura River delta is located in the Southwest Caspian Sea and is fluvial-dominated. The river distributes its sediment load through three channels oriented North-East, South-East, and South-West. The offshore modern delta consists of thinly bedded or laminated silty clays and dark grey clays. Locally sand and shell-rich horizons occur. Onshore delta is composed of channel-levee sands and floodplain silts and clays. Overall sedimentation rates in the delta determined by the 210Pb method range between 1.5-3.0 cm/yr. We investigated the distribution of organic material in the deltaic sediments in 300 samples selected from 3m deep piston cores. The studies of transparent sections demonstrate that deltaic sediments are enriched in terrestrial debris. It is non-transparent and has an irregular, isometric, or elongated shape, angular edges, black or dark-brown colour, and a clearly expressed fabric. Partially it is dissolved at the edges and is replaced by iron sulphides. Fragments of marine algae have more smooth edges, brown colour. They are transparent; the fabric is rarely preserved. The evidences of dissolution and gelification are well observed. Iron sulphides are common. The recorded third type of organic material has a round, drop-like, or oval shape and belongs to planktonic organisms. Their initial organic material is strongly transformed or replaced by dark organic compounds, probably, neoplasms. The particles are red-brown and transparent. The iron sulphides are not observed. The amount of Corg in the uppermost portion of sediments accumulated in the offshore Kura River delta varies from 0.2 to 1.22%, with median values of 0.6-0.8%. In poorly sorted sediments Corg content changes from 0.24 to 0.97% (average 0.69%), silty-sandy clay - 0.45 to 1.22% (average 0.77%), sandy-silty clay - 0.5 to 0.97% (average 0.67%), silty clay - 0.52 to 0.95% (average 0.70%). The data demonstrate that in sediments deposited during Caspian Sea high stand in 1929, the minimum of Corg content is localised near the mouth of the main south-eastern distributary channel and coincides with the minimum of the clay fraction. At the same time, the maximum of organic matter content locates near the mouth of the eastern channel, which was inactive at that time. In sediments accumulated during the last Caspian Sea low stand in 1977, the area of Corg minimum is attached to the north-eastern distributary’s mouth. It indicates the high activity of this distributary during the Caspian Sea fall. The area of Corg minimum is also recorded around the mouth of the main channel and eastern part of the delta. Maximums of Corg and clay fraction shift towards the basin. During the Caspian high stand in 1995, the minimum of Corg content is again observed in the mouth of the main south-eastern channel. The distribution of organic matter in the modern sediments of the Kura river delta displays the strong time dependence and reflects progradational-retrogradational cycles of evolution of this fluvial-deltaic system.

Keywords: high and low stands, Kura River delta, South Caspian Sea, organic matter

Procedia PDF Downloads 106