Connecting Lines Research Articles

Deep Cliques in Point Sets

Let n∈N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$n \\in \\mathbb {N}$$\\end{document} and k∈N0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$k \\in \\mathbb {N}_0$$\\end{document}. Given a set P of n points in the plane, a pair {p,q}\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\{p,q\\}$$\\end{document} of points in P is called k-deep, if there are at least k points from P strictly on each side of the line spanned by p and q. A k-deep clique is a subset of P with all its pairs k-deep. We show that if P is in general position (i.e., no three points on a line), there is a k-deep clique of size at least max{1,⌊nk+1⌋}\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\max \\{1,\\lfloor \\frac{n}{k+1} \\rfloor \\}$$\\end{document}; this is tight, for example in convex position. A k-deep clique in any set P of n points cannot have size exceeding n-⌈3k2⌉\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$n-\\lceil \\frac{3k}{2} \\rceil $$\\end{document}; this is tight for k≤n3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$k \\le \\frac{n}{3}$$\\end{document}. Moreover, for k≤⌊n2⌋-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$k \\le \\lfloor \\frac{n}{2} \\rfloor - 1$$\\end{document}, a k-deep clique cannot have size exceeding 2n(⌊n2⌋-k)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$2\\sqrt{n(\\lfloor \\frac{n}{2} \\rfloor -k)}$$\\end{document}; this is tight within a constant factor. We also pay special attention to (n2-1)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(\\frac{n}{2}-1)$$\\end{document}-deep cliques (for n even), which are called halving cliques. These have been considered in the literature by Khovanova and Yang, 2012, and they play a role in the latter bound above. Every set P in general position with a halving clique Q of size m must have at least ⌊(m-1)(m+3)2⌋\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\lfloor \\frac{(m-1)(m+3)}{2}\\rfloor $$\\end{document} points. If Q is in convex position, the set P must have size at least m(m-1)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$m(m-1)$$\\end{document}. This is tight, i.e., there are sets Qm\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Q_m$$\\end{document} of m points in convex position which can be extended to a set of m(m-1)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$m(m-1)$$\\end{document} points where Qm\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Q_m$$\\end{document} is a halving clique. Interestingly, this is not the case for all sets Q in convex position (even if parallel connecting lines among point pairs in Q are excluded).

Modelling and Simulation of a Stand-Alone Solar System with A Capacity of 380V, 39A Based On Ferrite Transformers and Half Cut Cell PV Modules

The easy installation of the solar energy system, no need for fuel, low maintenance and operation requirements, makes it the preferred choice to solve the problem of power outage especially in the day of the summer season. The downside of the solar energy systems is decreasing the generated energy with the rising in temperatures, perfect and simple design of the solar energy system makes it durable over a wide range of temperature increases. This research presents the design of 3-ph (380V, 39A) stand –alone solar system at latitude 32.5 with a high quality voltage and current even when the temperature reaches to maximum levels. The power system of the project contains: 60 PV modules of a half cut cell to reduce the losses in connection lines, and two Mn-Zn toroid core ferrite transformers to transition the solar energy to the inverter with appropriate voltage efficiently. Control system is implemented based on PI controllers for switching function at a certain values of a modulation index parameter (m). The system is modeled and simulated in MATLAM/Simulink, simulation results demonstrate that the rated voltage and current have been obtained with minimum values of Total Harmonics Distortion (THD) and modulation index parameter less than 1.

Nonlinear dynamic response analysis of a hybrid concrete‐filled steel tubular truss lightweight bridge under strong earthquakes

AbstractConcrete‐filled steel tubular (CFST) trusses have seen recent development and application in bridges found in mountainous regions with deep valleys, and especially in seismic zones. In this study, a hybrid CFST truss lightweight bridge was selected as the research object. This bridge is composited of CFST composite truss girders (superstructure) and CFST lattice piers (substructure). Two different finite element models (FEM) for nonlinear seismic response analysis, one is detailed model and the other is simplified model, were established. By comparing with the detailed model, the results of the shaking table test as well as the real bridge test, the simplified model was found to be accurate. Considering the CFST columns' edge strain, the most unfavorable input direction of horizontal ground motion was perpendicular to the connection line of the bearings at both ends of the main girder. Also, the simultaneous influence of vertical ground motion and horizontal ground motion needs to be taken into consideration. By increasing the intensity of input ground motion, the yielding order of CFST lattice piers and its effect on the seismic response were also discussed. Results indicated that the bridge was in the elastic stage for the designed seismic ground motion. After the CFST lattice piers reached the plastic stage, the displacement and in‐plane bending moment had larger amplification coefficients compared to the increase coefficient of the input ground motion, while had a much smaller axial force amplification coefficient. Moreover, the in‐plane bending moment had a larger amplification coefficient in high piers compared to short piers.

Control Strategy of Seamless Switching Between Grid-connected and Islanding Operation for Weak-connected Microgrid

A control strategy of seamless switching is proposed for the high-capacity microgrid, which is at the end of long-distance transmission. Firstly, the control modes of energy storage and diesel generator set under grid-connected conditions and islanding conditions are analyzed. Meanwhile, the seamless switching strategy for the microgrid, in which energy storage or diesel generator sets can be taken as the main power source adaptively, is proposed. During the switching from the grid-connected condition to the islanding condition, the connection line power is optimized according to the respective operational characteristics of the energy storage and diesel generator sets. And the interaction of the power step control with voltage blocking and the regulation characteristics of the line voltage regulator is utilized to effectively suppress the fluctuation of system voltage and frequency. Finally, the combination of auto-synchronization control and multiple synchronization control improves the success rate of switching from the islanding condition to the grid-connected condition. The on-site test results of an actual microgrid project verify the effectiveness of the proposed control strategy.

Experimental and numerical investigation on rock fracturing in tunnel contour blasting under initial stress

In tunnel contour blasting, the rock fracturing is generally subjected to in-situ stress. In this investigation, the rock cracking and damage in tunnel contour blasting (smooth blasting and presplitting) under various initial stresses are experimentally and numerically studied. Eight model tests are conducted on tunnel contour blasting with 400 × 400 × 50 mm granite plates. High-speed digital image correlation is employed to identify blast-induced rock fracturing, and image-processing with ImageJ is used to analyse the detailed fracture pattern and rock fragmentation. The variations in fracture networks, fragment size, fractal dimension of rock cracks and fractal damage to rock are thereby examined with increasing stress magnitude and stress dimension. Subsequently, the stress evolution and rock fracturing in model tests are simulated in LS-DYNA, and the energy dissipation during tunnel perimeter blasting is analysed. The investigation results demonstrate that initial stress results in the reduction of length and number of rock cracks under tunnel contour blasting, leading to smaller fractal dimension of crack pattern, less damage into rock and coarser rock fragmentation. Tunnel perimeter excavation performs well under low biaxial stress but tends to fail as the biaxial stress continually increases. Under uniaxial stress, smooth excavation peripheries can be achieved when the centreline of adjacent perimeter holes is parallel to the stress direction, while perimeter excavation is unsatisfactory when the connection line of adjoining boreholes is perpendicular to the initial stress. Comparing smooth blasting with presplitting, it is found that more explosion energy is consumed in rock fracturing during smooth blasting, especially in the excavation zone, leading to a better control of rock fracture and damage in tunnel contour excavation. Therefore, smooth blasting is preferentially recommended for deep tunnelling. Additionally, small burden is also recommended for deep tunnelling with smooth blasting to avoid potential oversize fragmentation in the excavation zone.

Effects of delay time on crack coalescence between two boreholes

Delayed detonation widely occurs in rock blasting, which has a significant influence on the propagation and interaction of explosion-induced stress waves. This affects the rock fracture interconnection between adjacent boreholes in controlled blasting. In this study, the effects of delay time on crack coalescence between two blastholes in contour blasting are experimentally, theoretically and numerically investigated. The rock cracking in two-hole blasting on 200 × 200 × 50 mm granite plate is first experimentally examined, in which the delay time is determined by high-speed photography and the rock fracturing is identified by digital image correlation. Then, two-hole blasting with delayed initiation is analytically modelled, and the fracture propagation behaviours in blast tests are explained based on the evolution of explosion-generated stress waves and peak stress distribution between two holes. Subsequently, 3D finite element models are built in LS-DYNA to simulate the evolution of explosion-produced pressure, rock fracturing and energy dissipation in two-hole controlled blasting with delayed initiation. The results indicate that in two-hole contour blasting, the stress superposition zone, which produces local stress enhancement in the vicinity of the stress wave collision point, moves closer to the later detonated hole. The superposed stress facilitates the preferential extension of blast-created cracks along the connection line of boreholes, and the crack from the later detonated hole extends farther than that from the first detonation hole. The optimal crack coalescence in contour blasting archives when the delay time allows stress waves to approximately propagate through the hole spacing.

Grid interface control of wind–solar generator in Hail region of Saudi Arabia using FOPI controller

This study investigates the performance of a wind–solar generator (WSG) in the Hail region of Kingdom of Saudi Arabia (KSA) with a fractional order PI controller (FOPI) applied to the grid connection line. The proposed hybrid generator consists of a wind turbine with a PMSM machine and a PV panel connected to a secondary distribution grid by a DC link, three-phase inverter, and an RL filter. The line currents injected into the grid and/or loads are controlled by calculating the output reference voltage of an inverter and by the reference active and reactive requested powers. For this purpose, control loops around the RL filter were developed with fractional-order proportional-integral (FOPI) controllers, and a comparison with classic PI controllers was made. The system was simulated using the MATLAB/Simulink software. The results showed that the generator satisfied the power demand under the climatic conditions of the Hail region. They also demonstrated the good performance of the proposed controllers, which had good tracking accuracy and robustness to variations in wind speed and power demanded by loads in a very short time. The FOPI controller exhibited faster dynamic response and less overshoot than the classic PI controller.

A new efficient algorithm for short path planning of the vertical take-off and landing air-ground integrated vehicle

With excellent air-ground multi-mode movements, the vertical take-off and landing (VTOL) air-ground integrated vehicle can easily traverse complex terrains and maintain high energy efficiency. During movement, path planning plays an important role in achieving the autonomous operation of the vehicle, which faces the following difficulty. A short air-ground multi-mode path requires efficient planning, with proper judgment of the timing and position for mode switching. To address this difficulty, we propose a new path planning algorithm, named Dynamically Directed Graph Algorithm (DDGA). It can realize short path search in limited search nodes via dynamically extracting key search nodes in maps and forming a dynamically directed graph. To be specific, adjacent nodes of the first obstacle traversed by the connection line from the current search node to the destination are defined as key search nodes. As the current node changes, key search nodes are dynamically updated. The above key search nodes and the directed paths between them form a dynamically directed graph. Considering the air-ground movement capability, obstacle areas below maximum flight altitudes in maps are defined as pending flight areas. The directed paths traversing these areas are considered in the above graph. Besides the two-dimensional distance cost, flight altitude cost is added to the cost values of different directed paths. This cost contributes to judging the proper switching timing and position. Compared to other algorithms, DDGA can find short paths with fewer search nodes in multiple obstacle maps. It efficiently plans a short air-ground multi-mode path for the VTOL air-ground integrated vehicle.

The goal and path of source network load storage coordination and interaction to help the construction of a new power system

Under the goal of “carbon peak and carbon neutral”, the characteristics of the power system mainly based on new energy will undergo significant changes. In order to solve the problem of insufficient power supply capacity caused by the precision of new energy generation, this paper puts forward the construction scheme of the new power system of source network, load, storage coordination, and interaction, and uses energy storage and flexible load adjustment to improve the transmission capacity of the connection line under emergency conditions. At the same time, energy storage centers and load aggregation providers are used to optimize the equivalent load under normal conditions and minimize the shortage of power supply capacity. Furthermore, the mathematical model of each index is established and the coordination level of source network load storage based on AHP-Delphi empowerment is proposed. Finally, the rationality of the actual planning scheme in the province is comprehensively evaluated, which provides a reference for the construction of the new power system.

Coronal Magnetic Field Extrapolation and Topological Analysis of Fine-scale Structures during Solar Flare Precursors

Magnetic field plays an important role in various solar eruption phenomena. The formation and evolution of the characteristic magnetic field topology in solar eruptions are critical problems that will ultimately help us understand the origin of these eruptions in the solar source regions. With the development of advanced techniques and instruments, observations with higher resolutions in different wavelengths and fields of view have provided more quantitative information for finer structures. It is therefore essential to improve the method with which we study the magnetic field topology in the solar source regions by taking advantage of high-resolution observations. In this study, we employ a nonlinear force-free field extrapolation method based on a nonuniform grid setting for an M-class flare eruption event (SOL2015-06-22T17:39) with embedded vector magnetograms from the Solar Dynamics Observatory (SDO) and the Goode Solar Telescope (GST). The extrapolation results for which the nonuniform embedded magnetogram for the bottom boundary was employed are obtained by maintaining the native resolutions of the corresponding GST and SDO magnetograms. We compare the field line connectivity with the simultaneous GST/Hα and SDO/Atmospheric Imaging Assembly observations for these fine-scale structures, which are associated with precursor brightenings. Then we perform a topological analysis of the field line connectivity corresponding to fine-scale magnetic field structures based on the extrapolation results. The analysis results indicate that when we combine the high-resolution GST magnetogram with a larger magnetogram from the SDO, the derived magnetic field topology is consistent with a scenario of magnetic reconnection among sheared field lines across the main polarity inversion line during solar flare precursors.

Analysis of electronic properties of hexagonal and triangular Bismuth quantum dot with different edges in the presence of magnetic field

We investigate energy spectra of Bi honeycomb quantum dots (BiQDs) considering buckled hexagonal and triangular structures with zigzag and armchair edges. We apply the four-orbital tight-binding approach. By using of the probability density of states, we distinguish some edge states in the regime of the band gap of Bi monolayer. We see that the number of edge states of zigzag (armchair) triangular BiQDs is more than the number of edge states of zigzag (armchair) hexagonal BiQDs. Also, we investigated energy spectra of hexagonal and triangular BiQDs with zigzag and armchair edges in the presence of the perpendicular magnetic fields. In the low and strong magnetic fields, there are relativistic Landau levels in the electronic spectra of BiQDs (in the hexagonal and triangular boundary conditions). Moreover, we show that edge atoms have more important roles in the formation of the line connectors between i and |i+1| Landau levels of hexagonal BiQDs than ones that are in the triangular BiQDs. In the middle numbers of the magnetic fields, more states collapse into Landau levels in which bulk atoms have a significant role to constitute them in both hexagonal and triangular BiQDs. Furthermore as the same as Bi nanoribbon spectrum, there are some helical edge modes in the band gap regions of Bi monolayer in which edge atoms are responsible to form them. These helical edge modes have topological properties.

Guarding the central venous access device: a new solution for an old problem.

CLABSIs are a major concern in both the adult and pediatric patient population. Contamination of catheter hubs is a common cause of CLABSI. A novel, transparent line guard protects CVAD hubs from gross contamination. Central line-associated blood stream infections (CLABSIs) are a serious and potentially deadly complication in patients with a central venous access device (CVAD). CVADs play an essential role in modern medicine, serving as lifelines for many patients. To maintain safe and stable venous access, infection prevention bundles are used to help protect patients from complications such as CLABSI. Despite most CLABSIs being preventable, rates have been on the rise, often disproportionately impacting critically ill children. New solutions are needed to strengthen infection prevention bundles and protect CVADs from pathogen entry at catheter hubs and line connections. A novel, Food and Drug Administration-listed device has become available recently to guard CVADs from sources of gross contamination, addressing this apparent gap in infection prevention technology and practice.

Movement fracturing “the international” —or, what does it mean to give primacy to movement?

Movement fracturing “the international” —or, what does it mean to give primacy to movement?

Phase equilibria in the ZrO2-GdO1.5-TaO2.5 system at 1500 °C

Phase equilibria in the ZrO2-GdO1.5-TaO2.5 (ZGTO) system are experimentally investigated, and the differences between ZGTO and the existing ZrO2-YO1.5-TaO2.5 (ZYTO) are discussed. On Gd:Ta> 1 side, binary fluorite Gd3TaO7 is measured to be stable at 1500 °C, and ternary fluorite phase forms continuous solid solution from binary ZrO2-GdO1.5 to GdO1.5-TaO2.5. On Gd:Ta< 1 side, there is a large difference between ZGTO and ZYTO. Firstly, GdTa7O19 is unstable at 1500 °C, and GdTa3O9 shows large ZrO2 solubility and extends along Gd1/4Ta3/4O9/4-ZrO2 connecting line without introducing vacancies. Secondly, non-transformable tetragonal ZrO2 and GdTaO4 are in equilibrium with GdTa3O9 in ZGTO. Thirdly, the tetragonal ZrO2 in equilibrium with Ta2Zr6O17 and GdTa3O9 is transformable and has lower stabilizer content. For ZrO2-GdTaO4 section, tetragonal ZrO2 and GdTaO4 extend nearly along with Gd:Ta= 1 and exhibit smaller solubilities. This study is useful for thermodynamic assessment of ZGTO, and can help guide the design of novel thermal barrier coatings materials.

Experimental Study on Dynamic Characteristics of Saturated Soft Clay with Sand Interlayer under Unidirectional and Bidirectional Vibration

The marine and alluvial plains along the southeastern coast of China are widely distributed in sandy formations, including smaller sand lenses and interlayers. The interlayers of sand have a significant impact on the mechanical properties of soft clay. In this paper, a large number of undrained unidirectional and bidirectional cyclic loading tests for soft clay with sand interlayers were carried out by a dynamic triaxial test system. Test results show that, under unidirectional and bidirectional cyclic vibration, the area of the hysteresis loop decreases and the slope of the connecting line at both ends of the hysteresis loop increases with the increasing of frequency. For the same vibration frequency, the area of the bidirectional vibration hysteresis loop and the slope of the connecting line at both ends are smaller than that of the unidirectional cyclic vibration. Under the same dynamic stress ratio, cumulative axial deformation caused by unidirectional and bidirectional vibration increases with the increasing frequency. Under unidirectional vibration, dynamic elastic modulus decreases at first, and then increases with the increasing frequency. For the same frequency, dynamic elastic modulus of the sample increases with the increase in cycles. Due to the effect of radial cyclic stress, the curves of dynamic elastic modulus and damping ratio with frequency under bidirectional vibration are opposite to those under unidirectional vibration.

Dynamic seabed-anchor capacity enhancements for taut-moored floating offshore wind

Decarbonisation of global energy supply to meet Net Zero targets by 2050 requires rapid expansion of offshore wind [4]. Much of this growth will come from floating offshore wind (FOW) technology where seabeds are less congested, high energy wind resources are located and conventional fixed offshore wind is not practical [1]. The required scale of FOW requires a step change in mooring and anchoring technology compared to existing hydrocarbon solutions. New, efficient and reliable mooring and anchoring systems are essential to economically deliver the necessary FOW [1]. Taut mooring arrangements can be attractive for FOW turbines as they require less length and lighter synthetic mooring line than traditional chain catenary mooring arrangements. However, taut moorings transmit significantly higher mean and peak tensions to the anchor compared to catenary moorings. It is therefore important to fully quantify the capacity available from anchors during typical FOW load conditions, including dynamic effects.&#x0D; This study focuses on how a numerical anchor macro model, Ancmac [6], can be used to capture and quantify dynamic anchor-seabed capacity benefits such as from seabed added mass, [5] and viscous soil strength effects. These effects can enhance the dynamic anchor capacity and are not typically considered in anchor design. Typical mooring-floater fluid-structure interaction analyses also model the connection of the mooring lines to the seabed as a fixed pin connection and so seabed-anchor-mooring interactions are not typically considered. Ancmac can replace this fixed pin connection node at the seabed as it uses mechanical analogue components (e.g. spring-viscous-slider and mass) to simply and practically link forces on the anchor with anchor and chain movements in the time domain to determine the seabed response and the current available anchor capacity. This study presents an example case where Ancmac is used to model the response of an embedded plate anchor that is subjected to a high amplitude, short period (= 6 and 10 s) high mean load event (Figure 1a). The anchor loads , , are derived from applying a 1-50 year storm design loading event on a 15MW FOW turbine [3] with a taut mooring line configuration composed of high modulus synthetic polyester rope [8].&#x0D; Results show that if dynamic seabed benefits are not considered (purple line in Figure 1a), then a static anchor capacity of = 4.15 MN and corresponding anchor size of = 11.13 m2 is required (for an anchor buried in slightly overconsolidated soft clay =30 kPa and bearing capacity factor =12.42). If beneficial dynamic seabed enhancements are considered (shown by red lines ), then a lower initial static anchor capacity can be adopted =3.13 MN, which corresponds to a 25% decrease in the required anchor size (=8.41 m2). During the design loading event, as the applied anchor load, increases above the available static capacity, towards the maximum applied value, the anchor begins to move (Figure 1b) generating dynamic resistance from mobilising the non-linear viscous slider and added mass resistance components. The resistance in the viscous slider component is based on a model for the change in undrained strength with increasing equivalent strain rate (=, where is anchor diameter), as shown in Figure 1c. The resistance from the viscous slider component reaches a maximum at the time marked slightly after the peak of the applied mooring line loads, at time , as shown in Figure 1a-c. Reducing the period of the applied load (=10 s to 6 s) increased the added mass resistance as the anchor is subjected to higher accelerations. As a result, the anchor experienced significantly smaller (50% less) maximum displacement and reduced velocities. This comparison is also evident in Figure 1d, which compares the contributions of resistance forces from the spring-viscous-slider and added mass components.&#x0D; Ancmac can also capture the long-term enhancements in seabed strength and anchor capacity as a time-varying function of the life-cycle of seasonally varying, operational applied loads. This could, for example, further reduce the required anchor sizes, as can increase from beneficial long-term seabed consolidation effects [7]-[10]. These short and long-term seabed benefits that occur over the range of different loading timescales, and result in enhanced anchor capacities for loads that are relevant to FOW taut mooring configurations, will be further discussed during the presentation.

Smart Grid Outlier Detection Based on the Minorization-Maximization Algorithm.

Outliers can be generated in the power system due to aging system equipment, faulty sensors, incorrect line connections, etc. The existence of these outliers will pose a threat to the safe operation of the power system, reduce the quality of the data, affect the completeness and accuracy of the data, and thus affect the monitoring analysis and control of the power system. Therefore, timely identification and treatment of outliers are essential to ensure stable and reliable operation of the power system. In this paper, we consider the problem of detecting and localizing outliers in power systems. The paper proposes a Minorization-Maximization (MM) algorithm for outlier detection and localization and an estimation of unknown parameters of the Gaussian mixture model (GMM). To verify the performance of the method, we conduct simulation experiments by simulating different test scenarios in the IEEE 14-bus system. Numerical examples show that in the presence of outliers, the MM algorithm can detect outliers better than the traditional algorithm and can accurately locate outliers with a probability of more than 95%. Therefore, the algorithm provides an effective method for the handling of outliers in the power system, which helps to improve the monitoring analyzing and controlling ability of the power system and to ensure the stable and reliable operation of the power system.

Experimental study of interactions between focused waves and a point absorber wave energy converter

Predicting the response of point absorber wave energy converters (WECs) in extreme sea states is crucial for assessing their survivability. However, data are scarce and hydrodynamic understanding is limited. In order to simulate extreme wave conditions, laboratory-scale focused waves based on NewWave theory have been utilized. To investigate the interactions between focused waves and a point absorber WEC, a wave basin experiment has been conducted. Various parameters, including focusing amplitude and peak frequency have been examined across three different damping conditions. The motion response of the point absorber WEC and the corresponding mooring force have been measured over time. The experimental findings reveal that both the focused wave parameters and the damping values have a significant influence on the motion response and mooring force. It is shown that an increase in the focusing amplitude leads to a more intense motion response, while the mooring force is relatively insensitive to the focused amplitude/peak frequency when the end-stop spring is not compressed. The force in the connection line is maximized when the upper end-stop spring is compressed. As the peak frequency increases, the heave and surge responses decrease, whereas the maximum mooring force increases with peak frequency for a locked power take-off (PTO) system. Finally, the results indicate that optimizing the design of the power take-off system, including selecting appropriate damping values and stroke lengths for the translator, can significantly reduce the mooring load for extreme wave conditions.

Ebenen des philosophischen Textverstehens und ihre lesestrategische Bedeutung

This article presents a didactical concept for the development of disciplinary reading strategies with A-Level-Students in high schools. The basic idea comes from cognitive and learning psychology and has been transferred to subject-teaching-contexts in recent years. For the teaching of Philosophy, the authors diagnose the existence of a missing link between the challenges of a philosophical text comprehension that focus on primary understanding on the one hand and the methods offered on the other. They argue for the development of a concept of reading strategies that takes into view three levels of text comprehension that are relevant for a philosophical understanding: the conceptual-semantic-level, the logical-pragmatic-level and the text-structural-level. Following a systematic presentation of the concept and its implementation options, the authors discuss possible connecting lines between the acquisition of philosophical reading literacy in schools and in introductory seminars at universities.

Influence of Column Base Connections on the Cyclic Loading Performance of Double-Jointed Engineered Bamboo Columns

The cyclic loading performance of bamboo double-jointed components of different column base connection types was investigated through reversed cyclic loading tests and finite element analysis. Test results indicated that the types of column base connections played an important role in the failure modes of the engineered bamboo double-jointed columns: for an encased steel plate column base connection, the main failure mode was tensile fracture failure of the bamboo scrimber section at the bottom of the cladding plate; for a slotted-in steel plate column base connection, the main failure mode was splitting failure of the bamboo scrimber cross-grain at the bolt connection line at the bottom of the sheathing plate. The initial stiffness of the encased steel plate column base connection specimen was 41.8% higher than that of the slotted-in steel plate column base connection specimen, with the two specimens having similar average bearing capacities. The ductility ratio of the two specimens was below 3.0 due to the brittle failure nature of the engineered bamboo connections. The finite element model accurately predicted the ultimate bearing capacity of the double-jointed bamboo column members. The modeling error was within 12%, which was sufficient to satisfy the accuracy requirements for engineering purposes.