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inversion</title> <meta name="description" content="Search results for: phase inversion"> <meta name="keywords" content="phase inversion"> <meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=1, maximum-scale=1, user-scalable=no"> <meta charset="utf-8"> <link href="https://cdn.waset.org/favicon.ico" type="image/x-icon" rel="shortcut icon"> <link href="https://cdn.waset.org/static/plugins/bootstrap-4.2.1/css/bootstrap.min.css" rel="stylesheet"> <link href="https://cdn.waset.org/static/plugins/fontawesome/css/all.min.css" rel="stylesheet"> <link href="https://cdn.waset.org/static/css/site.css?v=150220211555" rel="stylesheet"> </head> <body> <header> <div class="container"> <nav class="navbar navbar-expand-lg navbar-light"> <a class="navbar-brand" href="https://waset.org"> <img src="https://cdn.waset.org/static/images/wasetc.png" alt="Open Science Research Excellence" title="Open Science Research Excellence" /> </a> <button class="d-block d-lg-none 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action="https://publications.waset.org/abstracts/search"> <div id="custom-search-input"> <div class="input-group"> <i class="fas fa-search"></i> <input type="text" class="search-query" name="q" placeholder="Author, Title, Abstract, Keywords" value="phase inversion"> <input type="submit" class="btn_search" value="Search"> </div> </div> </form> </div> </div> <div class="row mt-3"> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Commenced</strong> in January 2007</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Frequency:</strong> Monthly</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Edition:</strong> International</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Paper Count:</strong> 4562</div> </div> </div> </div> <h1 class="mt-3 mb-3 text-center" style="font-size:1.6rem;">Search results for: phase inversion</h1> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4562</span> Two-Step Inversion Method for Multi-mode Surface Waves</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ying%20Zhang">Ying Zhang</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Surface waves provide critical constraints about the earth's structure in the crust and upper mantle. However, different modes of Love waves with close group velocities often arrive at a similar time and interfere with each other. This problem is typical for Love waves at intermediate periods that travel through the oceanic lithosphere. Therefore, we developed a two-step inversion approach to separate the waveforms of the fundamental and first higher mode of Love waves. We first solve the phase velocities of the two modes and their amplitude ratios. The misfit function is based on the sum of phase differences among the station pairs. We then solve the absolute amplitudes of the two modes and their initial phases using obtained phase velocities and amplitude ratio. The separated waveforms of each mode from the two-step inversion method can be further used in surface wave tomography to improve model resolution. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=surface%20wave%20inversion" title="surface wave inversion">surface wave inversion</a>, <a href="https://publications.waset.org/abstracts/search?q=waveform%20separation" title=" waveform separation"> waveform separation</a>, <a href="https://publications.waset.org/abstracts/search?q=love%20waves" title=" love waves"> love waves</a>, <a href="https://publications.waset.org/abstracts/search?q=higher-mode%20interference" title=" higher-mode interference"> higher-mode interference</a> </p> <a href="https://publications.waset.org/abstracts/164271/two-step-inversion-method-for-multi-mode-surface-waves" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/164271.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">70</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4561</span> Application of Post-Stack and Pre-Stack Seismic Inversion for Prediction of Hydrocarbon Reservoirs in a Persian Gulf Gas Field</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Nastaran%20Moosavi">Nastaran Moosavi</a>, <a href="https://publications.waset.org/abstracts/search?q=Mohammad%20Mokhtari"> Mohammad Mokhtari</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Seismic inversion is a technique which has been in use for years and its main goal is to estimate and to model physical characteristics of rocks and fluids. Generally, it is a combination of seismic and well-log data. Seismic inversion can be carried out through different methods; we have conducted and compared post-stack and pre- stack seismic inversion methods on real data in one of the fields in the Persian Gulf. Pre-stack seismic inversion can transform seismic data to rock physics such as P-impedance, S-impedance and density. While post- stack seismic inversion can just estimate P-impedance. Then these parameters can be used in reservoir identification. Based on the results of inverting seismic data, a gas reservoir was detected in one of Hydrocarbon oil fields in south of Iran (Persian Gulf). By comparing post stack and pre-stack seismic inversion it can be concluded that the pre-stack seismic inversion provides a more reliable and detailed information for identification and prediction of hydrocarbon reservoirs. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=density" title="density">density</a>, <a href="https://publications.waset.org/abstracts/search?q=p-impedance" title=" p-impedance"> p-impedance</a>, <a href="https://publications.waset.org/abstracts/search?q=s-impedance" title=" s-impedance"> s-impedance</a>, <a href="https://publications.waset.org/abstracts/search?q=post-stack%20seismic%20inversion" title=" post-stack seismic inversion"> post-stack seismic inversion</a>, <a href="https://publications.waset.org/abstracts/search?q=pre-stack%20seismic%20inversion" title=" pre-stack seismic inversion"> pre-stack seismic inversion</a> </p> <a href="https://publications.waset.org/abstracts/54295/application-of-post-stack-and-pre-stack-seismic-inversion-for-prediction-of-hydrocarbon-reservoirs-in-a-persian-gulf-gas-field" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/54295.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">324</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4560</span> Preparation and Characterization of Antifouling Polysulfone Flat Sheet Membrane by Phase Inversion</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Bharti%20Saini">Bharti Saini</a>, <a href="https://publications.waset.org/abstracts/search?q=Sukanta%20K.%20Dash"> Sukanta K. Dash</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this work polymeric Nanofiltration (NF) membranes of polysulfone (PSF) (average molecular weight of 22400 Da) were prepared using polyethylene glycol (PEG) (average molecular weight of 200 Da) as an organic additive and ZnCl2 as an inorganic additive. Dimethyl acetamide (DMAc) was used as the solvent, and Deionised water as nonsolvent. The membranes were prepared by phase inversion (immersion precipitation) method. PEG 200 and ZnCl2 in varying concentration are directly added into the casting solution of PSF and DMAc. PEG 200 was used in concentration varying from 0 to 10 % (w/w) in the solution of PSF and DMAc, while ZnCl2 is varied from 0 to 2% (w/w). Membranes were characterized for surface morphology, water uptake, porosity and contact angle, with respect to concentration of PEG and ZnCl2. It was observed that with the increase in additive PEG 200, the porosity and hence, hydrophilicity increase. As a result, the number of pores increases as justified by the SEM analysis as well. The study revealed that the synergistic effect of PEG with ZnCl2 is more effective, and the best results were produced by the solution containing 2% PEG 200 and 1% ZnCl2. It was inferred that with the increase in concentration of additives, the pore size goes on decreasing. The membranes obtained gradually move from microfiltration range to nanofiltration range, and this change is primarily brought about by the addition of ZnCl2. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=membrane" title="membrane">membrane</a>, <a href="https://publications.waset.org/abstracts/search?q=phase%20inversion%20method" title=" phase inversion method"> phase inversion method</a>, <a href="https://publications.waset.org/abstracts/search?q=polysulfone" title=" polysulfone"> polysulfone</a>, <a href="https://publications.waset.org/abstracts/search?q=porous%20structure" title=" porous structure"> porous structure</a> </p> <a href="https://publications.waset.org/abstracts/59222/preparation-and-characterization-of-antifouling-polysulfone-flat-sheet-membrane-by-phase-inversion" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/59222.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">235</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4559</span> Tectonic Inversion Manifestations in the Jebel Rouas-Ruissate (Northeastern Tunisia)</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Aymen%20Arfaoui">Aymen Arfaoui</a>, <a href="https://publications.waset.org/abstracts/search?q=Abdelkader%20Soumaya"> Abdelkader Soumaya</a>, <a href="https://publications.waset.org/abstracts/search?q=Noureddine%20Ben%20Ayed"> Noureddine Ben Ayed</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The Rouas-Ruissateis a part of TunisianAtlas system. Analyze of the collected field data allowed us to propose a new interpretation for the main structural features of thisregion. Tectonic inversions along NE-SW trending fault of Zaghouan and holokinetic movements are the main factors controlling the architecture and geometry of the Jebel Rouas-Ruissate. The presence of breccias, Slumps, and synsedimentaryfaults along NW-SE and N-S trending major faults show that they were active during the Mesozoicextensionalepisodes. During Cenozoic inversion period, this structurewas shaped as imbricatefansformed byNE-SW trending thrust faults. The angularunconformitybetweenupperEocene- Oligocene, and Cretaceousdeposits reveals a compressive Eocene tectonic phase (called Pyrenean phase)occurred duringPaleocene-lower Eocene.The Triassicsaltsacted as a decollementlevel in the NE-SW trendingfault propagation fold model of the Rouas-Ruissate.The inversion of fault-slip data along the main regional fault zones reveals a coexistence of strike-slip and reverse fault stress regimes with NW-SE maximum horizontal stress(SHmax) characterizing the Alpine compressive phase (Upper Tortonian). <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=tunisia" title="tunisia">tunisia</a>, <a href="https://publications.waset.org/abstracts/search?q=imbricate%20fans" title=" imbricate fans"> imbricate fans</a>, <a href="https://publications.waset.org/abstracts/search?q=triassic%20decollement%20level" title=" triassic decollement level"> triassic decollement level</a>, <a href="https://publications.waset.org/abstracts/search?q=fault%20propagation%20fold" title=" fault propagation fold"> fault propagation fold</a> </p> <a href="https://publications.waset.org/abstracts/145448/tectonic-inversion-manifestations-in-the-jebel-rouas-ruissate-northeastern-tunisia" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/145448.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">152</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4558</span> The Inversion of Helical Twist Sense in Liquid Crystal by Spectroscopy Methods</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Anna%20Drzewicz">Anna Drzewicz</a>, <a href="https://publications.waset.org/abstracts/search?q=Marzena%20Tykarska"> Marzena Tykarska</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The chiral liquid crystal phases form the helicoidal structure, which is characterized by the helical pitch and the helical twist sense. In anticlinic smectic phase with antiferroelectric properties three types of helix temperature dependence have been obtained: increased helical pitch with temperature and right-handed helix, decreased helical pitch with temperature and left-handed helix and the inversion of both. The change of helical twist sense may be observed during the transition from one liquid crystal phase to another or within one phase for the same substance. According to Gray and McDonnell theory, the helical handedness depends on the absolute configuration of the assymetric carbon atom and its position related to the rigid core of the molecule. However, this theory does not explain the inversion of helical twist sense phenomenon. It is supposed, that it may be caused by the presence of different conformers with opposite handendess, which concentration may change with temperature. In this work, the inversion of helical twist sense in the chiral liquid crystals differing in the length of alkyl chain, in the substitution the benzene ring by fluorine atoms and in the type of helix handedness was tested by vibrational spectroscopy (infrared and raman spectroscopy) and by nuclear magnetic resonance spectroscopy. The results obtained from the vibrational spectroscopy confirm the presence of different conformers. Moreover, the analysis of nuclear magnetic resonance spectra is very useful to check, on which structural fragments the change of conformations are important for the change of helical twist sense. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=helical%20twist%20sense" title="helical twist sense">helical twist sense</a>, <a href="https://publications.waset.org/abstracts/search?q=liquid%20crystals" title=" liquid crystals"> liquid crystals</a>, <a href="https://publications.waset.org/abstracts/search?q=nuclear%20magnetic%20resonance%20spectroscopy" title=" nuclear magnetic resonance spectroscopy"> nuclear magnetic resonance spectroscopy</a>, <a href="https://publications.waset.org/abstracts/search?q=vibrational%20spectroscopy" title=" vibrational spectroscopy"> vibrational spectroscopy</a> </p> <a href="https://publications.waset.org/abstracts/95848/the-inversion-of-helical-twist-sense-in-liquid-crystal-by-spectroscopy-methods" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/95848.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">282</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4557</span> Inversion of Electrical Resistivity Data: A Review</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Shrey%20Sharma">Shrey Sharma</a>, <a href="https://publications.waset.org/abstracts/search?q=Gunjan%20Kumar%20Verma"> Gunjan Kumar Verma</a> </p> <p class="card-text"><strong>Abstract:</strong></p> High density electrical prospecting has been widely used in groundwater investigation, civil engineering and environmental survey. For efficient inversion, the forward modeling routine, sensitivity calculation, and inversion algorithm must be efficient. This paper attempts to provide a brief summary of the past and ongoing developments of the method. It includes reviews of the procedures used for data acquisition, processing and inversion of electrical resistivity data based on compilation of academic literature. In recent times there had been a significant evolution in field survey designs and data inversion techniques for the resistivity method. In general 2-D inversion for resistivity data is carried out using the linearized least-square method with the local optimization technique .Multi-electrode and multi-channel systems have made it possible to conduct large 2-D, 3-D and even 4-D surveys efficiently to resolve complex geological structures that were not possible with traditional 1-D surveys. 3-D surveys play an increasingly important role in very complex areas where 2-D models suffer from artifacts due to off-line structures. Continued developments in computation technology, as well as fast data inversion techniques and software, have made it possible to use optimization techniques to obtain model parameters to a higher accuracy. A brief discussion on the limitations of the electrical resistivity method has also been presented. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=inversion" title="inversion">inversion</a>, <a href="https://publications.waset.org/abstracts/search?q=limitations" title=" limitations"> limitations</a>, <a href="https://publications.waset.org/abstracts/search?q=optimization" title=" optimization"> optimization</a>, <a href="https://publications.waset.org/abstracts/search?q=resistivity" title=" resistivity "> resistivity </a> </p> <a href="https://publications.waset.org/abstracts/26692/inversion-of-electrical-resistivity-data-a-review" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/26692.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">365</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4556</span> Sum Capacity with Regularized Channel Inversion in Multi-Antenna Downlink Systems under Equal Power Constraint</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Attaullah%20Khawaja">Attaullah Khawaja</a>, <a href="https://publications.waset.org/abstracts/search?q=Amna%20Shabbir"> Amna Shabbir </a> </p> <p class="card-text"><strong>Abstract:</strong></p> Channel inversion is one of the simplest techniques for multiuser downlink systems with single-antenna users. In this paper regularized channel inversion under equal power constraint in the multiuser multiple input multiple output (MU-MIMO) broadcast channels has been considered. Sum capacity with plain channel inversion also known as Zero Forcing Beam Forming (ZFBF) and optimum sum capacity using Dirty Paper Coding (DPC) has also been investigated. Analysis and simulations show that regularization enhances the system performance and empower linear growth in Sum Capacity and specially work well at low signal to noise ratio (SNRs) regime. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=broadcast%20channel" title="broadcast channel">broadcast channel</a>, <a href="https://publications.waset.org/abstracts/search?q=channel%20inversion" title=" channel inversion"> channel inversion</a>, <a href="https://publications.waset.org/abstracts/search?q=multiple%20antenna%20multiple-user%20wireless" title=" multiple antenna multiple-user wireless"> multiple antenna multiple-user wireless</a>, <a href="https://publications.waset.org/abstracts/search?q=multiple-input%20multiple-output%20%28MIMO%29" title=" multiple-input multiple-output (MIMO)"> multiple-input multiple-output (MIMO)</a>, <a href="https://publications.waset.org/abstracts/search?q=regularization" title=" regularization"> regularization</a>, <a href="https://publications.waset.org/abstracts/search?q=dirty%20paper%20coding%20%28DPC%29" title=" dirty paper coding (DPC)"> dirty paper coding (DPC)</a>, <a href="https://publications.waset.org/abstracts/search?q=sum%20capacity" title=" sum capacity"> sum capacity</a> </p> <a href="https://publications.waset.org/abstracts/16732/sum-capacity-with-regularized-channel-inversion-in-multi-antenna-downlink-systems-under-equal-power-constraint" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/16732.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">527</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4555</span> Hybrid Gravity Gradient Inversion-Ant Colony Optimization Algorithm for Motion Planning of Mobile Robots</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Meng%20Wu">Meng Wu</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Motion planning is a common task required to be fulfilled by robots. A strategy combining Ant Colony Optimization (ACO) and gravity gradient inversion algorithm is proposed for motion planning of mobile robots. In this paper, in order to realize optimal motion planning strategy, the cost function in ACO is designed based on gravity gradient inversion algorithm. The obstacles around mobile robot can cause gravity gradient anomalies; the gradiometer is installed on the mobile robot to detect the gravity gradient anomalies. After obtaining the anomalies, gravity gradient inversion algorithm is employed to calculate relative distance and orientation between mobile robot and obstacles. The relative distance and orientation deduced from gravity gradient inversion algorithm is employed as cost function in ACO algorithm to realize motion planning. The proposed strategy is validated by the simulation and experiment results. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=motion%20planning" title="motion planning">motion planning</a>, <a href="https://publications.waset.org/abstracts/search?q=gravity%20gradient%20inversion%20algorithm" title=" gravity gradient inversion algorithm"> gravity gradient inversion algorithm</a>, <a href="https://publications.waset.org/abstracts/search?q=ant%20colony%20optimization" title=" ant colony optimization"> ant colony optimization</a> </p> <a href="https://publications.waset.org/abstracts/110462/hybrid-gravity-gradient-inversion-ant-colony-optimization-algorithm-for-motion-planning-of-mobile-robots" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/110462.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">137</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4554</span> Integration of Resistivity and Seismic Refraction Using Combine Inversion for Ancient River Findings at Sungai Batu, Lembah Bujang, Malaysia</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Rais%20Yusoh">Rais Yusoh</a>, <a href="https://publications.waset.org/abstracts/search?q=Rosli%20Saad"> Rosli Saad</a>, <a href="https://publications.waset.org/abstracts/search?q=Mokhtar%20Saidin"> Mokhtar Saidin</a>, <a href="https://publications.waset.org/abstracts/search?q=Fauzi%20Andika"> Fauzi Andika</a>, <a href="https://publications.waset.org/abstracts/search?q=Sabiu%20Bala%20Muhammad"> Sabiu Bala Muhammad</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Resistivity and seismic refraction profiling have become a common method in pre-investigations for visualizing subsurface structure. The integration of the methods could reduce an interpretation ambiguity. Both methods have their individual software packages for data inversion, but potential to combine certain geophysical methods are restricted; however, the research algorithms that have this functionality was existed and are evaluated personally. The interpretation of subsurface were improve by combining inversion data from both methods by influence each other models using closure coupling; thus, by implementing both methods to support each other which could improve the subsurface interpretation. These methods were applied on a field dataset from a pre-investigation for archeology in finding the ancient river. There were no major changes in the inverted model by combining data inversion for this archetype which probably due to complex geology. The combine data analysis provides an additional technique for interpretation such as an alluvium, which can have strong influence on the ancient river findings. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=ancient%20river" title="ancient river">ancient river</a>, <a href="https://publications.waset.org/abstracts/search?q=combine%20inversion" title=" combine inversion"> combine inversion</a>, <a href="https://publications.waset.org/abstracts/search?q=resistivity" title=" resistivity"> resistivity</a>, <a href="https://publications.waset.org/abstracts/search?q=seismic%20refraction" title=" seismic refraction"> seismic refraction</a> </p> <a href="https://publications.waset.org/abstracts/70821/integration-of-resistivity-and-seismic-refraction-using-combine-inversion-for-ancient-river-findings-at-sungai-batu-lembah-bujang-malaysia" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/70821.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">334</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4553</span> Effect of Air Gap Distance on the Structure of PVDF Hollow Fiber Membrane Contactors for Physical CO2 Absorption</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=J.%20Shiri">J. Shiri</a>, <a href="https://publications.waset.org/abstracts/search?q=A.%20Mansourizadeh"> A. Mansourizadeh</a>, <a href="https://publications.waset.org/abstracts/search?q=F.%20Faghih"> F. Faghih</a>, <a href="https://publications.waset.org/abstracts/search?q=H.%20Vaez"> H. Vaez</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this study, porous polyvinylidene fluoride (PVDF) hollow fiber membranes are fabricated via a wet phase-inversion Process and used in the gas–liquid membrane contactor for physical CO2 absorption. Effect of different air gap on the structure and CO2 flux of the membrane was investigated. The hollow fibers were prepared using the wet spinning process using a dope solution containing PVDF/NMP/Licl (18%, 78%, 4%) at the extrusion rate of 4.5ml/min and air gaps of 0, 7, 15cm. Water was used as internal and external coagulants. Membranes were characterized using various techniques such as Field Emission Scanning Electron Microscopy (FESEM), Gas permeation test, Critical Water Entry Pressure (CEPw) to select the best membrane structure for Co2 absorption. The characterization results showed that the prepared membrane at which air gap possess small pore size with high surface porosity and wetting resistance, which are favorable for gas absorption application air gap increased, CEPw had a decrease, but the N2 permeation was decreased. Surface porosity and also Co2 absorption was increased. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=porous%20PVDF%20hollow%20fiber%20membrane" title="porous PVDF hollow fiber membrane">porous PVDF hollow fiber membrane</a>, <a href="https://publications.waset.org/abstracts/search?q=CO2%20absorption" title=" CO2 absorption"> CO2 absorption</a>, <a href="https://publications.waset.org/abstracts/search?q=phase%20inversion" title=" phase inversion"> phase inversion</a>, <a href="https://publications.waset.org/abstracts/search?q=air%20gap" title=" air gap"> air gap</a> </p> <a href="https://publications.waset.org/abstracts/13420/effect-of-air-gap-distance-on-the-structure-of-pvdf-hollow-fiber-membrane-contactors-for-physical-co2-absorption" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/13420.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">392</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4552</span> Use of Quasi-3D Inversion of VES Data Based on Lateral Constraints to Characterize the Aquifer and Mining Sites of an Area Located in the North-East of Figuil, North Cameroon</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Fofie%20Kokea%20Ariane%20Darolle">Fofie Kokea Ariane Darolle</a>, <a href="https://publications.waset.org/abstracts/search?q=Gouet%20Daniel%20Herv%C3%A9"> Gouet Daniel Hervé</a>, <a href="https://publications.waset.org/abstracts/search?q=Koumetio%20Fid%C3%A8le"> Koumetio Fidèle</a>, <a href="https://publications.waset.org/abstracts/search?q=Yemele%20David"> Yemele David</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The electrical resistivity method is successfully used in this paper in order to have a clearer picture of the subsurface of the North-East ofFiguil in northern Cameroon. It is worth noting that this method is most often used when the objective of the study is to image the shallow subsoils by considering them as a set of stratified ground layers. The problem to be solved is very often environmental, and in this case, it is necessary to perform an inversion of the data in order to have a complete and accurate picture of the parameters of the said layers. In the case of this work, thirty-three (33) Schlumberger VES have been carried out on an irregular grid to investigate the subsurface of the study area. The 1D inversion applied as a preliminary modeling tool and in correlation with the mechanical drillings results indicates a complex subsurface lithology distribution mainly consisting of marbles and schists. Moreover, the quasi-3D inversion with lateral constraint shows that the misfit between the observed field data and the model response is quite good and acceptable with a value low than 10%. The method also reveals existence of two water bearing in the considered area. The first is the schist or weathering aquifer (unsuitable), and the other is the marble or the fracturing aquifer (suitable). The final quasi 3D inversion results and geological models indicate proper sites for groundwaters prospecting and for mining exploitation, thus allowing the economic development of the study area. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=electrical%20resistivity%20method" title="electrical resistivity method">electrical resistivity method</a>, <a href="https://publications.waset.org/abstracts/search?q=1D%20inversion" title=" 1D inversion"> 1D inversion</a>, <a href="https://publications.waset.org/abstracts/search?q=quasi%203D%20inversion" title=" quasi 3D inversion"> quasi 3D inversion</a>, <a href="https://publications.waset.org/abstracts/search?q=groundwaters" title=" groundwaters"> groundwaters</a>, <a href="https://publications.waset.org/abstracts/search?q=mining" title=" mining"> mining</a> </p> <a href="https://publications.waset.org/abstracts/144894/use-of-quasi-3d-inversion-of-ves-data-based-on-lateral-constraints-to-characterize-the-aquifer-and-mining-sites-of-an-area-located-in-the-north-east-of-figuil-north-cameroon" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/144894.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">155</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4551</span> A Structural and Magnetic Investigation of the Inversion Degree in Spinel NiFe2O4, ZnFe2O4 and Ni0.5Zn0.5Fe2O4 Ferrites Prepared by Soft Mechanochemical Synthesis</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Z.%20%C5%BD.%20Lazarevi%C4%87">Z. Ž. Lazarević</a>, <a href="https://publications.waset.org/abstracts/search?q=D.%20L.%20Sekuli%C4%87"> D. L. Sekulić</a>, <a href="https://publications.waset.org/abstracts/search?q=V.%20N.%20Ivanovski"> V. N. Ivanovski</a>, <a href="https://publications.waset.org/abstracts/search?q=N.%20%C5%BD.%20Rom%C4%8Devi%C4%87"> N. Ž. Romčević</a> </p> <p class="card-text"><strong>Abstract:</strong></p> NiFe2O4 (nickel ferrite), ZnFe2O4 (zinc ferrite) and Ni0.5Zn0.5Fe2O4 (nickel-zinc ferrite) were prepared by mechanochemical route in a planetary ball mill starting from mixture of the appropriate quantities of the Ni(OH)2/Fe(OH)3, Zn(OH)2/Fe(OH)3 and Ni(OH)2/Zn(OH)2/Fe(OH)3 hydroxide powders. In order to monitor the progress of chemical reaction and confirm phase formation, powder samples obtained after 25 h, 18 h and 10 h of milling were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), IR, Raman and Mössbauer spectroscopy. It is shown that the soft mechanochemical method, i.e. mechanochemical activation of hydroxides, produces high quality single phase ferrite samples in much more efficient way. From the IR spectroscopy of single phase samples it is obvious that energy of modes depends on the ratio of cations. It is obvious that all samples have more than 5 Raman active modes predicted by group theory in the normal spinel structure. Deconvolution of measured spectra allows one to conclude that all complex bands in the spectra are made of individual peaks with the intensities that vary from spectrum to spectrum. The deconvolution of Raman spectra allows to separate contributions of different cations to a particular type of vibration and to estimate the degree of inversion. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=ferrites" title="ferrites">ferrites</a>, <a href="https://publications.waset.org/abstracts/search?q=Raman%20spectroscopy" title=" Raman spectroscopy"> Raman spectroscopy</a>, <a href="https://publications.waset.org/abstracts/search?q=IR%20spectroscopy" title=" IR spectroscopy"> IR spectroscopy</a>, <a href="https://publications.waset.org/abstracts/search?q=M%C3%B6ssbauer%20measurements" title=" Mössbauer measurements"> Mössbauer measurements</a> </p> <a href="https://publications.waset.org/abstracts/32610/a-structural-and-magnetic-investigation-of-the-inversion-degree-in-spinel-nife2o4-znfe2o4-and-ni05zn05fe2o4-ferrites-prepared-by-soft-mechanochemical-synthesis" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/32610.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">454</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4550</span> Kalman Filter Gain Elimination in Linear Estimation</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Nicholas%20D.%20Assimakis">Nicholas D. Assimakis</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In linear estimation, the traditional Kalman filter uses the Kalman filter gain in order to produce estimation and prediction of the n-dimensional state vector using the m-dimensional measurement vector. The computation of the Kalman filter gain requires the inversion of an m x m matrix in every iteration. In this paper, a variation of the Kalman filter eliminating the Kalman filter gain is proposed. In the time varying case, the elimination of the Kalman filter gain requires the inversion of an n x n matrix and the inversion of an m x m matrix in every iteration. In the time invariant case, the elimination of the Kalman filter gain requires the inversion of an n x n matrix in every iteration. The proposed Kalman filter gain elimination algorithm may be faster than the conventional Kalman filter, depending on the model dimensions. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=discrete%20time" title="discrete time">discrete time</a>, <a href="https://publications.waset.org/abstracts/search?q=estimation" title=" estimation"> estimation</a>, <a href="https://publications.waset.org/abstracts/search?q=Kalman%20filter" title=" Kalman filter"> Kalman filter</a>, <a href="https://publications.waset.org/abstracts/search?q=Kalman%20filter%20gain" title=" Kalman filter gain"> Kalman filter gain</a> </p> <a href="https://publications.waset.org/abstracts/123040/kalman-filter-gain-elimination-in-linear-estimation" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/123040.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">196</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4549</span> Phase Control in Population Inversion Using Chirped Laser</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Avijit%20Datta">Avijit Datta</a> </p> <p class="card-text"><strong>Abstract:</strong></p> We have presented a phase control scheme in population transfer using chirped laser fields. A chirped pulse can do population transfer from one level to another level via adiabatic rapid passage accessible by one photon dipole transition. We propose to use a pair of phase-locked chirped pulses of the same frequency w(t) instead of a singly chirped-pulse frequency w(t). Simultaneous action of phase controlled interference in addition to rapid adiabatic passages due to chirped pulses lead to phase control over this population transfer dynamics. We have demonstrated the proposed phase control scheme over the population distribution from the initial level X(v=0,j=0) to C(v=2,j=1) level of hydrogen molecule using a pair of phase-locked and similarly chirped laser pulses. We have extended this two-level system to three-level 1+1 ladder system of hydrogen molecule from X level to final J(v=2,j=2) level via C intermediate level using two pairs of laser pulses having frequencies w(t) and w'(t) respectively and obtained laudable control over the population distribution among three levels. We also have presented some results of interference effects of w₁(t) and its third harmonics w₃(t). <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=phase%20control" title="phase control">phase control</a>, <a href="https://publications.waset.org/abstracts/search?q=population%20transfer" title=" population transfer"> population transfer</a>, <a href="https://publications.waset.org/abstracts/search?q=chirped%20laser%20pulses" title=" chirped laser pulses"> chirped laser pulses</a>, <a href="https://publications.waset.org/abstracts/search?q=rapid%20adiabatic%20passage" title=" rapid adiabatic passage"> rapid adiabatic passage</a>, <a href="https://publications.waset.org/abstracts/search?q=laser-molecule%20interaction" title=" laser-molecule interaction "> laser-molecule interaction </a> </p> <a href="https://publications.waset.org/abstracts/62398/phase-control-in-population-inversion-using-chirped-laser" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/62398.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">363</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4548</span> An Approach on Robust Multi Inversion of a Nonlinear Model for an Omni-Directional Mobile</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Fernando%20P.%20Silva">Fernando P. Silva</a>, <a href="https://publications.waset.org/abstracts/search?q=Valter%20J.%20S.%20Leite"> Valter J. S. Leite</a>, <a href="https://publications.waset.org/abstracts/search?q=Erivelton%20G.%20Nepomuceno"> Erivelton G. Nepomuceno</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this paper, a nonlinear controller design for an omnidirectional mobile is presented. The robot controller consists of an inner-loop controller and an outer-loop controller, the ﬁrst is designed using state feedback (robust allocation) and the second controller is designed based on Robust Multi Inversion (RMI) approach. The objective of RMI controller is rendering the robust inversion of the dynamic, when the model is affected by uncertainties. A model nonlinear MIMO of an omni-directional robot (small-league of Robocup) is used to simulate the RMI approach. The parameters of linear and nonlinear model are varied to cause modelling uncertainties among the model and the real model (real system) generating an error in inner-loop controller signal that must be compensated by RMI controller. The simulation test results show that the RMI is capable of compensating the uncertainties and keep the system stable and controlled under uncertainties. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=robust%20multi%20inversion" title="robust multi inversion">robust multi inversion</a>, <a href="https://publications.waset.org/abstracts/search?q=omni-directional%20robot" title=" omni-directional robot"> omni-directional robot</a>, <a href="https://publications.waset.org/abstracts/search?q=robocup" title=" robocup"> robocup</a>, <a href="https://publications.waset.org/abstracts/search?q=nonlinear%20control" title=" nonlinear control"> nonlinear control</a> </p> <a href="https://publications.waset.org/abstracts/7104/an-approach-on-robust-multi-inversion-of-a-nonlinear-model-for-an-omni-directional-mobile" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/7104.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">589</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4547</span> Visco-Acoustic Full Wave Inversion in the Frequency Domain with Mixed Grids</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Sheryl%20Avenda%C3%B1o">Sheryl Avendaño</a>, <a href="https://publications.waset.org/abstracts/search?q=Miguel%20Ospina"> Miguel Ospina</a>, <a href="https://publications.waset.org/abstracts/search?q=Hebert%20Montegranario"> Hebert Montegranario</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Full Wave Inversion (FWI) is a variant of seismic tomography for obtaining velocity profiles by an optimization process that combine forward modelling (or solution of wave equation) with the misfit between synthetic and observed data. In this research we are modelling wave propagation in a visco-acoustic medium in the frequency domain. We apply finite differences for the numerical solution of the wave equation with a mix between usual and rotated grids, where density depends on velocity and there exists a damping function associated to a linear dissipative medium. The velocity profiles are obtained from an initial one and the data have been modeled for a frequency range 0-120 Hz. By an iterative procedure we obtain an estimated velocity profile in which are detailed the remarkable features of the velocity profile from which synthetic data were generated showing promising results for our method. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=seismic%20inversion" title="seismic inversion">seismic inversion</a>, <a href="https://publications.waset.org/abstracts/search?q=full%20wave%20inversion" title=" full wave inversion"> full wave inversion</a>, <a href="https://publications.waset.org/abstracts/search?q=visco%20acoustic%20wave%20equation" title=" visco acoustic wave equation"> visco acoustic wave equation</a>, <a href="https://publications.waset.org/abstracts/search?q=finite%20diffrence%20methods" title=" finite diffrence methods"> finite diffrence methods</a> </p> <a href="https://publications.waset.org/abstracts/33694/visco-acoustic-full-wave-inversion-in-the-frequency-domain-with-mixed-grids" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/33694.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">461</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4546</span> Procedural Protocol for Dual Energy Computed Tomography (DECT) Inversion</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Rezvan%20Ravanfar%20Haghighi">Rezvan Ravanfar Haghighi</a>, <a href="https://publications.waset.org/abstracts/search?q=S.%20Chatterjee"> S. Chatterjee</a>, <a href="https://publications.waset.org/abstracts/search?q=Pratik%20Kumar"> Pratik Kumar</a>, <a href="https://publications.waset.org/abstracts/search?q=V.%20C.%20Vani"> V. C. Vani</a>, <a href="https://publications.waset.org/abstracts/search?q=Priya%20Jagia"> Priya Jagia</a>, <a href="https://publications.waset.org/abstracts/search?q=Sanjiv%20Sharma"> Sanjiv Sharma</a>, <a href="https://publications.waset.org/abstracts/search?q=Susama%20Rani%20Mandal"> Susama Rani Mandal</a>, <a href="https://publications.waset.org/abstracts/search?q=R.%20Lakshmy"> R. Lakshmy</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The dual energy computed tomography (DECT) aims at noting the HU(V) values for the sample at two different voltages V=V1, V2 and thus obtain the electron densities (ρe) and effective atomic number (Zeff) of the substance. In the present paper, we aim to obtain a numerical algorithm by which (ρe, Zeff) can be obtained from the HU(100) and HU(140) data, where V=100, 140 kVp. The idea is to use this inversion method to characterize and distinguish between the lipid and fibrous coronary artery plaques.With the idea to develop the inversion algorithm for low Zeff materials, as is the case with non calcified coronary artery plaque, we prepare aqueous samples whose calculated values of (ρe, Zeff) lie in the range (2.65×1023≤ ρe≤ 3.64×1023 per cc ) and (6.80≤ Zeff ≤ 8.90). We fill the phantom with these known samples and experimentally determine HU(100) and HU(140) for the same pixels. Knowing that the HU(V) values are related to the attenuation coefficient of the system, we present an algorithm by which the (ρe, Zeff) is calibrated with respect to (HU(100), HU(140)). The calibration is done with a known set of 20 samples; its accuracy is checked with a different set of 23 known samples. We find that the calibration gives the ρe with an accuracy of ± 4% while Zeff is found within ±1% of the actual value, the confidence being 95%.In this inversion method (ρe, Zeff) of the scanned sample can be found by eliminating the effects of the CT machine and also by ensuring that the determination of the two unknowns (ρe, Zeff) does not interfere with each other. It is found that this algorithm can be used for prediction of chemical characteristic (ρe, Zeff) of unknown scanned materials with 95% confidence level, by inversion of the DECT data. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=chemical%20composition" title="chemical composition">chemical composition</a>, <a href="https://publications.waset.org/abstracts/search?q=dual-energy%20computed%20tomography" title=" dual-energy computed tomography"> dual-energy computed tomography</a>, <a href="https://publications.waset.org/abstracts/search?q=inversion%20algorithm" title=" inversion algorithm"> inversion algorithm</a> </p> <a href="https://publications.waset.org/abstracts/38567/procedural-protocol-for-dual-energy-computed-tomography-dect-inversion" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/38567.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">438</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4545</span> Effects of the Compressive Eocene Tectonic Phase in the Bou Kornine-Ressas-Messella Structure and Surroundings (Northern Tunisia)</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Aymen%20Arfaoui">Aymen Arfaoui</a>, <a href="https://publications.waset.org/abstracts/search?q=Abdelkader%20Soumaya"> Abdelkader Soumaya</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The Messalla-Ressas-Bou Kornine (MRB) and Hammamet Korbous (HK) major trending North-South fault zones provide a good opportunity to show the effects of the Eocene compressive phase in northern Tunisia. They acted as paleogeographical boundaries during the Mesozoic and belonged to a significant strike-slip corridor called the «North-South Axis,» extending from the Saharan platform at the South to the Gulf of Tunis at the North. Our study area is situated in a relay zone between two significant strike-slip faults (HK and MRB), separating the Atlas domain from the Pelagian Block. We used a multidisciplinary approach, including fieldwork, stress inversion, and geophysical profiles, to argue the shortening event that affected the study region. The MRB and HK contractional duplex is a privileged area for a local stress field and stress nucleation. The stress inversion of fault slip data reveals an Eocene compression with NW-SE trending SHmax, reactivating most of the ancient Mesozoic normal faults in the region. This shortening phase is represented in the MRB belt by an angular unconformity between the Upper Eocene over various Cretaceous strata. The stress inversion data reveal a compressive tectonic with an average NW-SE trending Shmax. The major N-S faults are reactivated under this shortening as sinistral oblique faults. The orientation of SHmax deviates from NW-SE to E-W near the preexisting deep faults of MRB and HK. This E-W stress direction generated the emerging overlap of Ressas-Messella and blind thrust faults in the Cretaceous deposits. The connection of the sub-meridian reverse faults in depth creates "flower structures" under an E-W local compressive stress. In addition, we detected a reorientation of the SHmax into an N-S direction in the central part of the MRB - HK contractional duplex, creating E-W reverse faults and overlapping zones. Finally, the Eocene compression constituted the first major tectonic phase which inverted the Mesozoic preexisting extensive fault system in Northern Tunisia. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=Tunisia" title="Tunisia">Tunisia</a>, <a href="https://publications.waset.org/abstracts/search?q=eocene%20compression" title=" eocene compression"> eocene compression</a>, <a href="https://publications.waset.org/abstracts/search?q=tectonic%20stress%20field" title=" tectonic stress field"> tectonic stress field</a>, <a href="https://publications.waset.org/abstracts/search?q=Bou%20Kornine-Ressas-Messella" title=" Bou Kornine-Ressas-Messella"> Bou Kornine-Ressas-Messella</a> </p> <a href="https://publications.waset.org/abstracts/159370/effects-of-the-compressive-eocene-tectonic-phase-in-the-bou-kornine-ressas-messella-structure-and-surroundings-northern-tunisia" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/159370.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">72</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4544</span> Dependence of the Photoelectric Exponent on the Source Spectrum of the CT</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Rezvan%20Ravanfar%20Haghighi">Rezvan Ravanfar Haghighi</a>, <a href="https://publications.waset.org/abstracts/search?q=V.%20C.%20Vani"> V. C. Vani</a>, <a href="https://publications.waset.org/abstracts/search?q=Suresh%20%20Perumal"> Suresh Perumal</a>, <a href="https://publications.waset.org/abstracts/search?q=Sabyasachi%20Chatterjee"> Sabyasachi Chatterjee</a>, <a href="https://publications.waset.org/abstracts/search?q=Pratik%20Kumar"> Pratik Kumar</a> </p> <p class="card-text"><strong>Abstract:</strong></p> X-ray attenuation coefficient [µ(E)] of any substance, for energy (E), is a sum of the contributions from the Compton scattering [ μCom(E)] and photoelectric effect [µPh(E)]. In terms of the, electron density (ρe) and the effective atomic number (Zeff) we have µCom(E) is proportional to [(ρe)fKN(E)] while µPh(E) is proportional to [(ρeZeffx)/Ey] with fKN(E) being the Klein-Nishina formula, with x and y being the exponents for photoelectric effect. By taking the sample's HU at two different excitation voltages (V=V1, V2) of the CT machine, we can solve for X=ρe, Y=ρeZeffx from these two independent equations, as is attempted in DECT inversion. Since µCom(E) and µPh(E) are both energy dependent, the coefficients of inversion are also dependent on (a) the source spectrum S(E,V) and (b) the detector efficiency D(E) of the CT machine. In the present paper we tabulate these coefficients of inversion for different practical manifestations of S(E,V) and D(E). The HU(V) values from the CT follow: <µ(V)>=<µw(V)>[1+HU(V)/1000] where the subscript 'w' refers to water and the averaging process <….> accounts for the source spectrum S(E,V) and the detector efficiency D(E). Linearity of μ(E) with respect to X and Y implies that (a) <µ(V)> is a linear combination of X and Y and (b) for inversion, X and Y can be written as linear combinations of two independent observations <µ(V1)>, <µ(V2)> with V1≠V2. These coefficients of inversion would naturally depend upon S(E, V) and D(E). We numerically investigate this dependence for some practical cases, by taking V = 100 , 140 kVp, as are used for cardiological investigations. The S(E,V) are generated by using the Boone-Seibert source spectrum, being superposed on aluminium filters of different thickness lAl with 7mm≤lAl≤12mm and the D(E) is considered to be that of a typical Si[Li] solid state and GdOS scintilator detector. In the values of X and Y, found by using the calculated inversion coefficients, errors are below 2% for data with solutions of glycerol, sucrose and glucose. For low Zeff materials like propionic acid, Zeffx is overestimated by 20% with X being within1%. For high Zeffx materials like KOH the value of Zeffx is underestimated by 22% while the error in X is + 15%. These imply that the source may have additional filtering than the aluminium filter specified by the manufacturer. Also it is found that the difference in the values of the inversion coefficients for the two types of detectors is negligible. The type of the detector does not affect on the DECT inversion algorithm to find the unknown chemical characteristic of the scanned materials. The effect of the source should be considered as an important factor to calculate the coefficients of inversion. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=attenuation%20coefficient" title="attenuation coefficient">attenuation coefficient</a>, <a href="https://publications.waset.org/abstracts/search?q=computed%20tomography" title=" computed tomography"> computed tomography</a>, <a href="https://publications.waset.org/abstracts/search?q=photoelectric%20effect" title=" photoelectric effect"> photoelectric effect</a>, <a href="https://publications.waset.org/abstracts/search?q=source%20spectrum" title=" source spectrum"> source spectrum</a> </p> <a href="https://publications.waset.org/abstracts/38566/dependence-of-the-photoelectric-exponent-on-the-source-spectrum-of-the-ct" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/38566.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">400</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4543</span> Inversion of Gravity Data for Density Reconstruction</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Arka%20Roy">Arka Roy</a>, <a href="https://publications.waset.org/abstracts/search?q=Chandra%20Prakash%20Dubey"> Chandra Prakash Dubey</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Inverse problem generally used for recovering hidden information from outside available data. Vertical component of gravity field we will be going to use for underneath density structure calculation. Ill-posing nature is main obstacle for any inverse problem. Linear regularization using Tikhonov formulation are used for appropriate choice of SVD and GSVD components. For real time data handle, signal to noise ratios should have to be less for reliable solution. In our study, 2D and 3D synthetic model with rectangular grid are used for gravity field calculation and its corresponding inversion for density reconstruction. Fine grid also we have considered to hold any irregular structure. Keeping in mind of algebraic ambiguity factor number of observation point should be more than that of number of data point. Picard plot is represented here for choosing appropriate or main controlling Eigenvalues for a regularized solution. Another important study is depth resolution plot (DRP). DRP are generally used for studying how the inversion is influenced by regularizing or discretizing. Our further study involves real time gravity data inversion of Vredeforte Dome South Africa. We apply our method to this data. The results include density structure is in good agreement with known formation in that region, which puts an additional support of our method. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=depth%20resolution%20plot" title="depth resolution plot">depth resolution plot</a>, <a href="https://publications.waset.org/abstracts/search?q=gravity%20inversion" title=" gravity inversion"> gravity inversion</a>, <a href="https://publications.waset.org/abstracts/search?q=Picard%20plot" title=" Picard plot"> Picard plot</a>, <a href="https://publications.waset.org/abstracts/search?q=SVD" title=" SVD"> SVD</a>, <a href="https://publications.waset.org/abstracts/search?q=Tikhonov%20formulation" title=" Tikhonov formulation"> Tikhonov formulation</a> </p> <a href="https://publications.waset.org/abstracts/74339/inversion-of-gravity-data-for-density-reconstruction" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/74339.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">212</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4542</span> Abnormal Features of Two Quasiparticle Rotational Bands in Rare Earths</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Kawalpreet%20Kalra">Kawalpreet Kalra</a>, <a href="https://publications.waset.org/abstracts/search?q=Alpana%20Goel"> Alpana Goel</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The behaviour of the rotational bands should be smooth but due to large amount of inertia and decreased pairing it is not so. Many experiments have been done in the last few decades, and a large amount of data is available for comprehensive study in this region. Peculiar features like signature dependence, signature inversion, and signature reversal are observed in many two quasiparticle rotational bands of doubly odd and doubly even nuclei. At high rotational frequencies, signature and parity are the only two good quantum numbers available to label a state. Signature quantum number is denoted by α. Even-angular momentum states of a rotational band have α =0, and the odd-angular momentum states have α =1. It has been observed that the odd-spin members lie lower in energy up to a certain spin Ic; the normal signature dependence is restored afterwards. This anomalous feature is termed as signature inversion. The systematic of signature inversion in high-j orbitals for doubly odd rare earth nuclei have been done. Many unusual features like signature dependence, signature inversion and signature reversal are observed in rotational bands of even-even/odd-odd nuclei. Attempts have been made to understand these phenomena using several models. These features have been analyzed within the framework of the Two Quasiparticle Plus Rotor Model (TQPRM). <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=rotational%20bands" title="rotational bands">rotational bands</a>, <a href="https://publications.waset.org/abstracts/search?q=signature%20dependence" title=" signature dependence"> signature dependence</a>, <a href="https://publications.waset.org/abstracts/search?q=signature%20quantum%20number" title=" signature quantum number"> signature quantum number</a>, <a href="https://publications.waset.org/abstracts/search?q=two%20quasiparticle" title=" two quasiparticle"> two quasiparticle</a> </p> <a href="https://publications.waset.org/abstracts/84944/abnormal-features-of-two-quasiparticle-rotational-bands-in-rare-earths" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/84944.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">168</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4541</span> Seismic Inversion to Improve the Reservoir Characterization: Case Study in Central Blue Nile Basin, Sudan</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Safwat%20E.%20Musa">Safwat E. Musa</a>, <a href="https://publications.waset.org/abstracts/search?q=Nuha%20E.%20Mohamed"> Nuha E. Mohamed</a>, <a href="https://publications.waset.org/abstracts/search?q=Nuha%20A.%20Bagi"> Nuha A. Bagi </a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this study, several crossplots of the P-impedance with the lithology logs (gamma ray, neutron porosity, deep resistivity, water saturation and Vp/Vs curves) were made in three available wells, which were drilled in central part of the Blue Nile basin in depths varies from 1460 m to 1600 m. These crossplots were successful to discriminate between sand and shale when using P-Impedance values, and between the wet sand and the pay sand when using both P-impedance and Vp/Vs together. Also, some impedance sections were converted to porosity sections using linear formula to characterize the reservoir in terms of porosity. The used crossplots were created on log resolution, while the seismic resolution can identify only the reservoir, unless a 3D seismic angle stacks were available; then it would be easier to identify the pay sand with great confidence; through high resolution seismic inversion and geostatistical approach when using P-impedance and Vp/Vs volumes. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=basin" title="basin">basin</a>, <a href="https://publications.waset.org/abstracts/search?q=Blue%20Nile" title=" Blue Nile"> Blue Nile</a>, <a href="https://publications.waset.org/abstracts/search?q=inversion" title=" inversion"> inversion</a>, <a href="https://publications.waset.org/abstracts/search?q=seismic" title=" seismic"> seismic</a> </p> <a href="https://publications.waset.org/abstracts/19111/seismic-inversion-to-improve-the-reservoir-characterization-case-study-in-central-blue-nile-basin-sudan" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/19111.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">430</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4540</span> The Effects of Water Fraction and Salinity on Crude Oil-Water Dispersions</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ramin%20Dabirian">Ramin Dabirian</a>, <a href="https://publications.waset.org/abstracts/search?q=Yi%20Zhang"> Yi Zhang</a>, <a href="https://publications.waset.org/abstracts/search?q=Ilias%20Gavrielatos"> Ilias Gavrielatos</a>, <a href="https://publications.waset.org/abstracts/search?q=Ram%20Mohan"> Ram Mohan</a>, <a href="https://publications.waset.org/abstracts/search?q=Ovadia%20Shoham"> Ovadia Shoham</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Oil-water emulsions can be found in almost every part of the petroleum industry, namely in reservoir rocks, drilling cuttings circulation, production in wells, transportation pipelines, surface facilities and refining process. However, it is necessary for oil production and refinery engineers to resolve the petroleum emulsion problems as well as to eliminate the contaminants in order to meet environmental standards, achieve the desired product quality and to improve equipment reliability and efficiency. A state-of-art Dispersion Characterization Rig (DCR) has been utilized to investigate crude oil-distilled water dispersion separation. Over 80 experimental tests were ran to investigate the flow behavior and stability of the dispersions. The experimental conditions include the effects of water cuts (25%, 50% and 75%), NaCl concentrations (0, 3.5% and 18%), mixture flow velocities (0.89 and 1.71 ft/s), and also orifice place types on the separation rate. The experimental data demonstrate that the water cut can significantly affects the separation time and efficiency. The dispersion with lower water cut takes longer time to separate and have low separation efficiency. The medium and lower water cuts will result in the formation of Mousse emulsion and the phase inversion happens around the medium water cut. The data also confirm that increasing the NaCl concentration in aqueous phase can increase the crude oil water dispersion separation efficiency especially at higher salinities. The separation profile for dispersions with lower salt concentrations has a lower sedimentation rate slope before the inflection point. Dispersions in all tests with higher salt concentrations have a larger sedimenting rate. The presence of NaCl can influence the interfacial tension gradients along the interface and it plays a role in avoiding the Mousse emulsion formation. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=oil-water%20dispersion" title="oil-water dispersion">oil-water dispersion</a>, <a href="https://publications.waset.org/abstracts/search?q=separation%20mechanism" title=" separation mechanism"> separation mechanism</a>, <a href="https://publications.waset.org/abstracts/search?q=phase%20inversion" title=" phase inversion"> phase inversion</a>, <a href="https://publications.waset.org/abstracts/search?q=emulsion%20formation" title=" emulsion formation"> emulsion formation</a> </p> <a href="https://publications.waset.org/abstracts/93258/the-effects-of-water-fraction-and-salinity-on-crude-oil-water-dispersions" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/93258.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">181</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4539</span> Seismic Inversion for Geothermal Exploration</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=E.%20N.%20Masri">E. N. Masri</a>, <a href="https://publications.waset.org/abstracts/search?q=E.%20Tak%C3%A1cs"> E. Takács</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Amplitude Versus Offset (AVO) and simultaneous model-based impedance inversion techniques have not been utilized for geothermal exploration commonly; however, some recent publications called the attention that they can be very useful in the geothermal investigations. In this study, we present rock physical attributes obtained from 3D pre-stack seismic data and well logs collected in a study area of the NW part of Pannonian Basin where the geothermal reservoir is located in the fractured zones of Triassic basement and it was hit by three productive-injection well pairs. The holes were planned very successfully based on the conventional 3D migrated stack volume prior to this study. Subsequently, the available geophysical-geological datasets provided a great opportunity to test modern inversion procedures in the same area. In this presentation, we provide a summary of the theory and application of the most promising seismic inversion techniques from the viewpoint of geothermal exploration. We demonstrate P- and S-wave impedance, as well as the velocity (Vp and Vs), the density, and the Vp/Vs ratio attribute volumes calculated from the seismic and well-logging data sets. After a detailed discussion, we conclude that P-wave impedance and Vp/Vp ratio are the most helpful parameters for lithology discrimination in the study area. They detect the hot water saturated fracture zone very well thus they can be very useful in mapping the investigated reservoir. Integrated interpretation of all the obtained rock-physical parameters is essential. We are extending the above discussed pre-stack seismic tools by studying the possibilities of Elastic Impedance Inversion (EII) for geothermal exploration. That procedure provides two other useful rock-physical properties, the compressibility and the rigidity (Lamé parameters). Results of those newly created elastic parameters will also be demonstrated in the presentation. Geothermal extraction is of great interest nowadays; and we can adopt several methods have been successfully applied in the hydrocarbon exploration for decades to discover new reservoirs and reduce drilling risk and cost. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=fractured%20zone" title="fractured zone">fractured zone</a>, <a href="https://publications.waset.org/abstracts/search?q=seismic" title=" seismic"> seismic</a>, <a href="https://publications.waset.org/abstracts/search?q=well-logging" title=" well-logging"> well-logging</a>, <a href="https://publications.waset.org/abstracts/search?q=inversion" title=" inversion"> inversion</a> </p> <a href="https://publications.waset.org/abstracts/155865/seismic-inversion-for-geothermal-exploration" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/155865.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">126</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4538</span> The Implementation of Poisson Impedance Inversion to Improve Hydrocarbon Reservoir Characterization in Poseidon Field, Browse Basin, Australia</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Riky%20Tri%20Hartagung">Riky Tri Hartagung</a>, <a href="https://publications.waset.org/abstracts/search?q=Mohammad%20Syamsu%20Rosid"> Mohammad Syamsu Rosid</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The lithology prediction process, as well as the fluid content is the most important part in the reservoir characterization. One of the methods used in this process is the simultaneous seismic inversion method. In the Posseidon field, Browse Basin, Australia, the parameters generated through simultaneous seismic inversion are not able to characterize the reservoir accurately because of the overlapping impedance values between hydrocarbon sand, water sand, and shale, which causes a high level of ambiguity in the interpretation. The Poisson Impedance inversion provides a solution to this problem by rotating the impedance a few degrees, which is obtained through the coefficient c. Coefficient c is obtained through the Target Correlation Coefficient Analysis (TCCA) by finding the optimum correlation coefficient between Poisson Impedance and the target log, namely gamma ray, effective porosity, and resistivity. Correlation of each of these target logs will produce Lithology Impedance (LI) which is sensitive to lithology sand, Porosity Impedance (ϕI) which is sensitive to porous sand, and Fluid Impedance (FI) which is sensitive to fluid content. The results show that PI gives better results in separating hydrocarbon saturated reservoir zones. Based on the results of the LI-GR crossplot, the ϕI-effective porosity crossplot, and the FI-Sw crossplot with optimum correlations of 0.74, 0.91, and 0.82 respectively, it shows that the lithology of hidrocarbon-saturated porous sand is at the value of LI ≤ 2800 (m/s)(g *cc), ϕI ≤ 5500 (m/s)(g*cc), and FI ≤ 4000 (m/s)(g*cc). The presence of low values of LI, ϕI, and FI correlates accurately with the presence of hydrocarbons in the well. Each value of c is then applied to the seismic data. The results show that the PI inversion gives a good distribution of Hydrocarbon-saturated porous sand lithology. The distribution of hydrocarbon saturated porous sand on the seismic inversion section is seen in the northeast – southwest direction, which is estimated as the direction of gas distribution. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=reservoir%20characterization" title="reservoir characterization">reservoir characterization</a>, <a href="https://publications.waset.org/abstracts/search?q=poisson%20impedance" title=" poisson impedance"> poisson impedance</a>, <a href="https://publications.waset.org/abstracts/search?q=browse%20basin" title=" browse basin"> browse basin</a>, <a href="https://publications.waset.org/abstracts/search?q=poseidon%20field" title=" poseidon field"> poseidon field</a> </p> <a href="https://publications.waset.org/abstracts/148389/the-implementation-of-poisson-impedance-inversion-to-improve-hydrocarbon-reservoir-characterization-in-poseidon-field-browse-basin-australia" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/148389.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">124</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4537</span> Performance Investigation of UAV Attitude Control Based on Modified PI-D and Nonlinear Dynamic Inversion</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ebrahim%20Hassan%20Kapeel">Ebrahim Hassan Kapeel</a>, <a href="https://publications.waset.org/abstracts/search?q=Ahmed%20Mohsen%20Kamel"> Ahmed Mohsen Kamel</a>, <a href="https://publications.waset.org/abstracts/search?q=Hossan%20Hendy"> Hossan Hendy</a>, <a href="https://publications.waset.org/abstracts/search?q=Yehia%20Z.%20Elhalwagy"> Yehia Z. Elhalwagy</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Interest in autopilot design has been raised intensely as a result of recent advancements in Unmanned Aerial vehicles (UAVs). Due to the enormous number of applications that UAVs can achieve, the number of applied control theories used for them has increased in recent years. These small fixed-wing UAVs are suffering high non-linearity, sensitivity to disturbances, and coupling effects between their channels. In this work, the nonlinear dynamic inversion (NDI) control lawisdesigned for a nonlinear small fixed-wing UAV model. The NDI is preferable for varied operating conditions, there is no need for a scheduling controller. Moreover, it’s applicable for high angles of attack. For the designed flight controller validation, a nonlinear Modified PI-D controller is performed with our model. A comparative study between both controllers is achieved to evaluate the NDI performance. Simulation results and analysis are proposed to illustrate the effectiveness of the designed controller based on NDI. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=UAV%20dynamic%20model" title="UAV dynamic model">UAV dynamic model</a>, <a href="https://publications.waset.org/abstracts/search?q=attitude%20control" title=" attitude control"> attitude control</a>, <a href="https://publications.waset.org/abstracts/search?q=nonlinear%20PID" title=" nonlinear PID"> nonlinear PID</a>, <a href="https://publications.waset.org/abstracts/search?q=dynamic%20inversion" title=" dynamic inversion"> dynamic inversion</a> </p> <a href="https://publications.waset.org/abstracts/150437/performance-investigation-of-uav-attitude-control-based-on-modified-pi-d-and-nonlinear-dynamic-inversion" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/150437.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">110</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4536</span> Performance Investigation of Unmanned Aerial Vehicles Attitude Control Based on Modified PI-D and Nonlinear Dynamic Inversion</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ebrahim%20H.%20Kapeel">Ebrahim H. Kapeel</a>, <a href="https://publications.waset.org/abstracts/search?q=Ahmed%20M.%20Kamel"> Ahmed M. Kamel</a>, <a href="https://publications.waset.org/abstracts/search?q=Hossam%20Hendy"> Hossam Hendy</a>, <a href="https://publications.waset.org/abstracts/search?q=Yehia%20Z.%20Elhalwagy"> Yehia Z. Elhalwagy</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Interest in autopilot design has been raised intensely as a result of recent advancements in Unmanned Aerial vehicles (UAVs). Due to the enormous number of applications that UAVs can achieve, the number of applied control theories used for them has increased in recent years. These small fixed-wing UAVs are suffering high non-linearity, sensitivity to disturbances, and coupling effects between their channels. In this work, the nonlinear dynamic inversion (NDI) control law is designed for a nonlinear small fixed-wing UAV model. The NDI is preferable for varied operating conditions, there is no need for a scheduling controller. Moreover, it’s applicable for high angles of attack. For the designed flight controller validation, a nonlinear Modified PI-D controller is performed with our model. A comparative study between both controllers is achieved to evaluate the NDI performance. Simulation results and analysis are proposed to illustrate the effectiveness of the designed controller based on NDI. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=attitude%20control" title="attitude control">attitude control</a>, <a href="https://publications.waset.org/abstracts/search?q=nonlinear%20PID" title=" nonlinear PID"> nonlinear PID</a>, <a href="https://publications.waset.org/abstracts/search?q=dynamic%20inversion" title=" dynamic inversion"> dynamic inversion</a> </p> <a href="https://publications.waset.org/abstracts/149836/performance-investigation-of-unmanned-aerial-vehicles-attitude-control-based-on-modified-pi-d-and-nonlinear-dynamic-inversion" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/149836.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">111</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4535</span> Derivation of Bathymetry from High-Resolution Satellite Images: Comparison of Empirical Methods through Geographical Error Analysis</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Anusha%20P.%20Wijesundara">Anusha P. Wijesundara</a>, <a href="https://publications.waset.org/abstracts/search?q=Dulap%20I.%20Rathnayake"> Dulap I. Rathnayake</a>, <a href="https://publications.waset.org/abstracts/search?q=Nihal%20D.%20Perera"> Nihal D. Perera</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Bathymetric information is fundamental importance to coastal and marine planning and management, nautical navigation, and scientific studies of marine environments. Satellite-derived bathymetry data provide detailed information in areas where conventional sounding data is lacking and conventional surveys are inaccessible. The two empirical approaches of log-linear bathymetric inversion model and non-linear bathymetric inversion model are applied for deriving bathymetry from high-resolution multispectral satellite imagery. This study compares these two approaches by means of geographical error analysis for the site Kankesanturai using WorldView-2 satellite imagery. Based on the Levenberg-Marquardt method calibrated the parameters of non-linear inversion model and the multiple-linear regression model was applied to calibrate the log-linear inversion model. In order to calibrate both models, Single Beam Echo Sounding (SBES) data in this study area were used as reference points. Residuals were calculated as the difference between the derived depth values and the validation echo sounder bathymetry data and the geographical distribution of model residuals was mapped. The spatial autocorrelation was calculated by comparing the performance of the bathymetric models and the results showing the geographic errors for both models. A spatial error model was constructed from the initial bathymetry estimates and the estimates of autocorrelation. This spatial error model is used to generate more reliable estimates of bathymetry by quantifying autocorrelation of model error and incorporating this into an improved regression model. Log-linear model (R²=0.846) performs better than the non- linear model (R²=0.692). Finally, the spatial error models improved bathymetric estimates derived from linear and non-linear models up to R²=0.854 and R²=0.704 respectively. The Root Mean Square Error (RMSE) was calculated for all reference points in various depth ranges. The magnitude of the prediction error increases with depth for both the log-linear and the non-linear inversion models. Overall RMSE for log-linear and the non-linear inversion models were ±1.532 m and ±2.089 m, respectively. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=log-linear%20model" title="log-linear model">log-linear model</a>, <a href="https://publications.waset.org/abstracts/search?q=multi%20spectral" title=" multi spectral"> multi spectral</a>, <a href="https://publications.waset.org/abstracts/search?q=residuals" title=" residuals"> residuals</a>, <a href="https://publications.waset.org/abstracts/search?q=spatial%20error%20model" title=" spatial error model "> spatial error model </a> </p> <a href="https://publications.waset.org/abstracts/90872/derivation-of-bathymetry-from-high-resolution-satellite-images-comparison-of-empirical-methods-through-geographical-error-analysis" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/90872.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">297</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4534</span> Local Radial Basis Functions for Helmholtz Equation in Seismic Inversion</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Hebert%20Montegranario">Hebert Montegranario</a>, <a href="https://publications.waset.org/abstracts/search?q=Mauricio%20Londo%C3%B1o"> Mauricio Londoño </a> </p> <p class="card-text"><strong>Abstract:</strong></p> Solutions of Helmholtz equation are essential in seismic imaging methods like full wave inversion, which needs to solve many times the wave equation. Traditional methods like Finite Element Method (FEM) or Finite Differences (FD) have sparse matrices but may suffer the so called pollution effect in the numerical solutions of Helmholtz equation for large values of the wave number. On the other side, global radial basis functions have a better accuracy but produce full matrices that become unstable. In this research we combine the virtues of both approaches to find numerical solutions of Helmholtz equation, by applying a meshless method that produce sparse matrices by local radial basis functions. We solve the equation with absorbing boundary conditions of the kind Clayton-Enquist and PML (Perfect Matched Layers) and compared with results in standard literature, showing a promising performance by tackling both the pollution effect and matrix instability. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=Helmholtz%20equation" title="Helmholtz equation">Helmholtz equation</a>, <a href="https://publications.waset.org/abstracts/search?q=meshless%20methods" title=" meshless methods"> meshless methods</a>, <a href="https://publications.waset.org/abstracts/search?q=seismic%20imaging" title=" seismic imaging"> seismic imaging</a>, <a href="https://publications.waset.org/abstracts/search?q=wavefield%20inversion" title=" wavefield inversion"> wavefield inversion</a> </p> <a href="https://publications.waset.org/abstracts/33679/local-radial-basis-functions-for-helmholtz-equation-in-seismic-inversion" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/33679.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">547</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4533</span> A TgCNN-Based Surrogate Model for Subsurface Oil-Water Phase Flow under Multi-Well Conditions</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Jian%20Li">Jian Li</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The uncertainty quantification and inversion problems of subsurface oil-water phase flow usually require extensive repeated forward calculations for new runs with changed conditions. To reduce the computational time, various forms of surrogate models have been built. Related research shows that deep learning has emerged as an effective surrogate model, while most surrogate models with deep learning are purely data-driven, which always leads to poor robustness and abnormal results. To guarantee the model more consistent with the physical laws, a coupled theory-guided convolutional neural network (TgCNN) based surrogate model is built to facilitate computation efficiency under the premise of satisfactory accuracy. The model is a convolutional neural network based on multi-well reservoir simulation. The core notion of this proposed method is to bridge two separate blocks on top of an overall network. They underlie the TgCNN model in a coupled form, which reflects the coupling nature of pressure and water saturation in the two-phase flow equation. The model is driven by not only labeled data but also scientific theories, including governing equations, stochastic parameterization, boundary, and initial conditions, well conditions, and expert knowledge. The results show that the TgCNN-based surrogate model exhibits satisfactory accuracy and efficiency in subsurface oil-water phase flow under multi-well conditions. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=coupled%20theory-guided%20convolutional%20neural%20network" title="coupled theory-guided convolutional neural network">coupled theory-guided convolutional neural network</a>, <a href="https://publications.waset.org/abstracts/search?q=multi-well%20conditions" title=" multi-well conditions"> multi-well conditions</a>, <a href="https://publications.waset.org/abstracts/search?q=surrogate%20model" title=" surrogate model"> surrogate model</a>, <a href="https://publications.waset.org/abstracts/search?q=subsurface%20oil-water%20phase" title=" subsurface oil-water phase"> subsurface oil-water phase</a> </p> <a href="https://publications.waset.org/abstracts/159365/a-tgcnn-based-surrogate-model-for-subsurface-oil-water-phase-flow-under-multi-well-conditions" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/159365.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">86</span> </span> </div> </div> <ul class="pagination"> <li class="page-item disabled"><span class="page-link">&lsaquo;</span></li> <li class="page-item active"><span class="page-link">1</span></li> <li class="page-item"><a class="page-link" href="https://publications.waset.org/abstracts/search?q=phase%20inversion&page=2">2</a></li> <li class="page-item"><a class="page-link" href="https://publications.waset.org/abstracts/search?q=phase%20inversion&page=3">3</a></li> <li class="page-item"><a class="page-link" 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