Experimental and numerical analysis of the squat and resistance of ships advancing through the new Suez Canal

When a ship is sailing in shallow and restricted waters such as harbours and canals, it is usually accompanied by obvious sinkage and trim, called squat. The ship squat has important influences on ship hydrodynamic performance in shallow and restricted water such as ship resistance. Squat is caused by the drop in pressure under the bottom of the ship, where the relative speed of the water is higher. Due to the squat effect, the hydrodynamic forces on the ship will increase largely, ship control will become difficult and risks of grounding may increase. A new division of the Suez Canal is called New Suez Canal, recently opened for international navigation. It is important to obtain accurate prediction data for ship squat to minimise the risk of grounding in this canal. Accurate prediction of the squat is of great significance to correctly evaluate ship hydrodynamic performance and to ensure navigation safety in the New Suez Canal. In this study, various methods for prediction of ship squat were conducted and introduced. A series of experiments were conducted with a model scale of the KRISO Container Ship (KCS) at 1:75 scale. The squat of the KCS was examined by measuring its sinkage, trim and resistance. The influences of ship speed, water depth, ship-bank distance on the squat and blockage effect were analysed. The results indicated that for Froude's number based on depth (Fnh) below 0.4, measured squat values do not change with either Fnh or depth to draft ratio (H/T). The squat increases with H/T values for the depth Froude numbers higher than 0.4. Moreover, a ship's speed can be increased to up to 9 knots inside the New Suez Canal with no adverse effects, thus significantly reducing the time for a ship to pass through the Canal. Next, the study of reduced the Canal width to 62.5% of its real-life cross sectional area, no significant effect was observed on ship squat. Moreover, a series of experimental tests were conducted at loading conditions under different trimming angles to examine the range of ship trim for safe and efficient sailing in canals. to detect the best trim angle for ships during sailing in restricted waters to reduce resistance and therefore fuel consumption.;The results show that for depth Froude's numbers higher than 0.4, the ship model sinkage is less for aft trim than for level trim or forward trim. Concurrently, it can be observed that there is less water resistance for aft trim than for forward trim, albeit level trim shows the least resistance. Furthermore, the present study combines numerical, analytical and empirical methods for a holistic approach in calm water. As a case-study, the KCS hullform is adopted, and analysed experimentally, via Computational Fluid Dynamics, using the slender body theory, and empirical formulae. The results reveal strong effect between the canal's cross section and all examined parameters. In addition, CFD calculations proved to be a reliable tool for predicting ship performance while navigating shallow and restricted waters. CFD simulations in multiphase and double body regime are performed to reveal the form factor and wave resistance of the KCS. This is performed in two different canals while varying the depth Froude number. The results suggest a dependency of the form factor on ship speed. Analytical and empirical methods were used for comparison, the slender body theory, provided good predictions in the low speed range, but did not agree well with the experimental data at high speeds. To model the sloping canal sides of the Suez Canal via the slender body theory, a rectangular canal with equivalent blockage was constructed, which may have influenced the accuracy of the theory.When a ship is sailing in shallow and restricted waters such as harbours and canals, it is usually accompanied by obvious sinkage and trim, called squat. The ship squat has important influences on ship hydrodynamic performance in shallow and restricted water such as ship resistance. Squat is caused by the drop in pressure under the bottom of the ship, where the relative speed of the water is higher. Due to the squat effect, the hydrodynamic forces on the ship will increase largely, ship control will become difficult and risks of grounding may increase. A new division of the Suez Canal is called New Suez Canal, recently opened for international navigation. It is important to obtain accurate prediction data for ship squat to minimise the risk of grounding in this canal. Accurate prediction of the squat is of great significance to correctly evaluate ship hydrodynamic performance and to ensure navigation safety in the New Suez Canal. In this study, various methods for prediction of ship squat were conducted and introduced. A series of experiments were conducted with a model scale of the KRISO Container Ship (KCS) at 1:75 scale. The squat of the KCS was examined by measuring its sinkage, trim and resistance. The influences of ship speed, water depth, ship-bank distance on the squat and blockage effect were analysed. The results indicated that for Froude's number based on depth (Fnh) below 0.4, measured squat values do not change with either Fnh or depth to draft ratio (H/T). The squat increases with H/T values for the depth Froude numbers higher than 0.4. Moreover, a ship's speed can be increased to up to 9 knots inside the New Suez Canal with no adverse effects, thus significantly reducing the time for a ship to pass through the Canal. Next, the study of reduced the Canal width to 62.5% of its real-life cross sectional area, no significant effect was observed on ship squat. Moreover, a series of experimental tests were conducted at loading conditions under different trimming angles to examine the range of ship trim for safe and efficient sailing in canals. to detect the best trim angle for ships during sailing in restricted waters to reduce resistance and therefore fuel consumption.;The results show that for depth Froude's numbers higher than 0.4, the ship model sinkage is less for aft trim than for level trim or forward trim. Concurrently, it can be observed that there is less water resistance for aft trim than for forward trim, albeit level trim shows the least resistance. Furthermore, the present study combines numerical, analytical and empirical methods for a holistic approach in calm water. As a case-study, the KCS hullform is adopted, and analysed experimentally, via Computational Fluid Dynamics, using the slender body theory, and empirical formulae. The results reveal strong effect between the canal's cross section and all examined parameters. In addition, CFD calculations proved to be a reliable tool for predicting ship performance while navigating shallow and restricted waters. CFD simulations in multiphase and double body regime are performed to reveal the form factor and wave resistance of the KCS. This is performed in two different canals while varying the depth Froude number. The results suggest a dependency of the form factor on ship speed. Analytical and empirical methods were used for comparison, the slender body theory, provided good predictions in the low speed range, but did not agree well with the experimental data at high speeds. To model the sloping canal sides of the Suez Canal via the slender body theory, a rectangular canal with equivalent blockage was constructed, which may have influenced the accuracy of the theory

Dutch media: pillarization, multiculturalism, and cross-culturalism

‘Media and culture’ has been always a topic of interest and study, not only for scholars, but for policy makers and the general public as well. The topic is very broad. It includes defending cultural autonomy in face of the influences of globalized media, in addition to using media as a tool for preserving multiculturalism in societies and for integrating minorities. This paper explores the media system of the Netherlands (the Low Countries), also known as Holland, through the phenomenon of ‘pillarization’ in the media and its development towards ‘multiculturalism’ and ‘cross-culturalism’. Furthermore, it sheds light on the influence of these developments on minorities in the Netherlands

Use of social media by governments to enhance online civic engagement: The case of Egypt

This research examines the extent to which the use of social media by the Egyptian government in its communication with the public enhances online civic engagement. Its importance lies in the fact that several studies highlighted the benefits of the utilization of social media by governments in engaging with the public. This thesis defines civic engagement as the involvement of citizens in online activities that seek to address public issues through the social media platforms of the Egyptian government. It focuses on the five types of online civic engagement behavior as described by Denning (2001), i.e. collection of information, publication of information, dialogue, coordination of action, and lobbying decision makers. This study employs content analysis. Over a period of 15 months, a probability, simple random sample of 491 posts by three Facebook pages of Egyptian ministries and 2287 comments by the public on these Pages was analyzed. It reached four main conclusions. First, the Egyptian ministries use of social media contributes poorly to the strengthening of online civic engagement. Second, a linear, one-way model characterizes the type of communication conducted by the Egyptian ministries. Third, the content of the interaction of the public with the government provides evidence that citizens are active in exploiting the ministries’ social media to voice their opinions, lobby decision makers, and raise questions. Finally, though there is marginal interaction between the ministries and the public, citizens are more engaged into dialogue amongst themselves. Thus, this research concludes that social media is an untapped communication resource in the context of its utilization by the Egyptian government. Consequently, this study fills a gap in the literature and could encourage other researchers to tackle that topic from its different aspects

Atmospheric Pollution Measurements with Tunable Lasers Employing Resonance Absorption

Theoretical and experimental techniques, which are useful in molecular spectroscopic studies and in the development of Laser Absorption Spectrometers (LAS), are described. Both fixed-frequency and tunable lasers have been employed. All the measurements reported are based on either direct or second harmonic absorption techniques. A commercial CO/CO₂ line-tunable laser has been used to obtain useful criteria for air pollution monitoring via the direct absorption scheme. CO₂ laser absorption measurements on ozone at reduced pressures are reported. Measurements on seventeen NO absorption lines with a CO laser are described. For these, the absolute absorption as a function of pressure has been determined. As a result we have been able to establish accurate values for the absorption of NO at the pertinent CO laser wavelengths. From the best fit between experimental measurements and theoretical calculations we have deduced the separation between the appropriate NO and CO wavelengths, the NO/N₂ pressure broadening, the NO band strength, and the individual NO line strengths. Using a tunable lead-salt semiconductor diode laser, and employing the direct absorption technique, we have developed a simple method for accurate frequency, measurements of ozone absorption lines. This technique is based on employing a tunable semiconductor diode laser, an etalon, and a White cell. We report accurate frequency meaaurements of over 100 absorption lines of ozone in the ν₃ band, which are near the CO₂ laser transitions. Despite the relative simplicity of the technique, we achieved an accuracy of better than 10 MHz in our measurements. This accuracy compares well with that achieved by the more complicated heterodyne techniques of high-resolution spectroscopy. However, these are the first measurements over an entire absorption band using the full resolution of a tunable diode laser. A LAS, which combines the sensitivity of the acousto-optical methods with the convenience of direct, long-path optical detection, is described. The diode laser is wavelength modulated and the second harmonic detection technique is applied. This technique enables us to detect atmospheric pollutant gases with extremely high sensitivity (3 ppb of a weak absorbing pollutant such as SO₂ in its ν₁ band or 3 x 10ˉ³ ppb of a strongly absorbing molecule such as CO). This sensitivity is achieved using a frequency-locking technique for the diode. We report on the detection of O₃, SO₂, NH₃, and N₂O pollutants at their ambient, levels in air. A very high specificity and virtual elimination of interference effects are obtained by sampling the atmospheric air at reduced pressures. A remote LAS station, which is considered to be adjunct to the above LAS, has been built. A remote retroreflector and an off-axis telescope near the laser have been employed to achieve a total pathlength of 1.2 km in the atmosphere. We report theoretical and experimental investigations of SO₂, H₂O, NH₃ and H₂O absorption in the region 1100 - 1200ˉ¹ cm at atmospheric pressure. This enabled us to develop a technique, based on the second harmonic detection scheme, to detect SO₂ in the atmosphere with a sensitivity of 50 ppb employing a diode laser emitting in the ν₁ band of SO₂. We report also on spectroscopic studies and absorption measurements for SO₂ and H₂O in the region 1300 - 1400 cmˉ¹. These studies indicate that it is possible to detect SO₂ with ambient levels in the atmosphere by employing a diode laser radiating in the ν₃ band of SO₂, near 1331.5 cmˉ¹. In all the above mentioned techniques, theoretical calculations of laser transmission through the atmosphere must be predicted prior to applying such techniques. For this reason, a computer package has been developed and tested. This package generates the absorption line parameters of any molecule, even asymmetric-top molecules, in the vibration-rotation infrared region. The absorption (transmission) can be calculated at any pressure.Doctor of Philosophy (PhD

Differential effects of clinically used derivatives and metabolites of artemisinin in the activation of constitutive androstane receptor isoforms

BACKGROUND AND PURPOSE Widespread resistance to antimalarial drugs requires combination therapies with increasing risk of pharmacokinetic drugdrug interactions. Here, we explore the capacity of antimalarial drugs to induce drug metabolism via activation of constitutive androstane receptors (CAR) by ligand binding. EXPERIMENTAL APPROACH A total of 21 selected antimalarials and 11 major metabolites were screened for binding to CAR isoforms using cellular and in vitro CAR-coactivator interaction assays, combined with in silico molecular docking. Identified ligands were further characterized by cell-based assays and primary human hepatocytes were used to elucidate induction of gene expression. KEY RESULTS Only two artemisinin derivatives arteether and artemether, the metabolite deoxyartemisinin and artemisinin itself demonstrated agonist binding to the major isoforms CAR1 and CAR3, while arteether and artemether were also inverse agonists of CAR2. Dihydroartemisinin and artesunate acted as weak inverse agonists of CAR1. While arteether showed the highest activities in vitro, it was less active than artemisinin in inducing hepatic CYP3A4 gene expression in hepatocytes. CONCLUSIONS AND IMPLICATIONS Artemisinin derivatives and metabolites differentially affect the activities of CAR isoforms and of the pregnane X receptor (PXR). This negates a common effect of these drugs on CAR/PXR-dependent induction of drug metabolism and further provides an explanation for artemisinin consistently inducing cytochrome P450 genes in vivo, whereas arteether and artemether do not. All these drugs are metabolized very rapidly, but only artemisinin is converted to an enzyme-inducing metabolite. For better understanding of pharmacokinetic drugdrug interaction possibilities, the inducing properties of artemisinin metabolites should be considered.German Federal Ministry of Education and Research (BMBF) HepatosSys network [0313081B, 0313080F, 0313080I]; Deutsche Forschungsgemeinschaft (Germany) [KE 1629/1-1]; Robert Bosch Foundation, Stuttgart, Germanyinfo:eu-repo/semantics/publishedVersio

Comparative Evaluation for Torque Control Strategies of Interior Permanent Magnet Synchronous Motor for Electric Vehicles

This paper presents a detailed analysis and comparative investigation for the torque control techniques of interior permanent magnet synchronous motor (IPMSM) for electric vehicles (EVs). The study involves the field-oriented control (FOC), direct torque control (DTC), and model predictive direct torque control (MPDTC) techniques. The control aims to achieve vehicle requirements that involve maximum torque per ampere (MTPA), minimum torque ripples, maximum efficiency, fast dynamics, and wide speed range. The MTPA is achieved by the direct calculation of reference flux-linkage as a function of commanded torque. The calculation of reference flux-linkage is done online by the solution of a quartic equation. Therefore, it is a more practical solution compared to look-up table methods that depend on machine parameters and require extensive offline calculations in advance. For realistic results, the IPMSM model is built considering iron losses. Besides, the IGBTs and diodes losses (conduction and switching losses) in power inverter are modeled and calculated to estimate properly total system efficiency. In addition, a bidirectional dc-dc boost converter is connected to the battery to improve the overall drive performance and achieve higher efficiency values. Also, instead of the conventional PI controller which suffers from parameter variation, the control scheme includes an adaptive fuzzy logic controller (FLC) to provide better speed tracking performance. It also provides a better robustness against disturbance and uncertainties. Finally, a series of simulation results with detailed analysis are executed for a 60 kW IPMSM. The electric vehicle (EV) parameters are equivalent to Nissan Leaf 2018 electric car