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Designing and developing smart antennas with adaptive radiation characteristics is an integral part for present-day communication systems. The versatile capabilities of Time-modulated fourth-dimensional (4D) antenna arrays can provide that crucial adaptability if properly designed. This work discusses an effective analysis of 4D antenna arrays to achieve less-attenuating radiation patterns with simultaneously suppressed sidelobe and sidebands. The 4D arrays offer an additional benefit over standard arrays in the sense that the requisite amplitude tapering to lower the undesired radiations can be accomplished by controlling only the switch ON times of the radiating elements instead of using attenuators. The idea of splitting pulses by keeping the total switch ON durations constant, is exploited here as an additional degree of freedom for beamforming of all the radiation patterns. The unwanted radiations in terms of sidelobes as well as sideband radiations (SRs) at the fundamental and harmonic frequencies, respectively are simultaneously minimized to improve the radiation efficiencies of the 4D array. To address the conflicting aims for the synthesis of radiation patterns, a wavelet-mutation based heuristic method is also proposed. The multi-objective problem in hand is modulated in to a single objective cost function as minimization problem. The proposed outcomes are reported and compared with other state of the art works related to the same domain. Furthermore, a detailed statistical analysis is also provided to identify the strengths and weaknesses of the proposed approach.
The history of the laws of war is an increasingly popular research field of international law. Claire Vergerio’s book War, States, and International Order: Alberico Gentili and the Foundational Myth of the Laws of War is a good-read in this regard. It provides a critical analysis of how 19th-century international lawyers misread and reinterpreted the writings of the 16th-century Italian jurist Alberico Gentili to establish the modern sovereign state as the sole legitimate subject of the laws of war. In this review essay, I offer a critical reading of War, States and International Order, positioning its intervention in the context of broader scholarly debates.
Here, we explore variation in a new record of archaeological house-floor sizes from the southwestern United States relative to spatially explicit time series estimates of local precipitation. Our results show that inequality becomes more severe during periods of high precipitation. This supports the theory suggesting that inequality may emerge where resources are dense, predictable, and clumped within heterogenous and circumscribed environments. Our findings indicate that wealth inequality may emerge among populations with similar subsistence adaptations as a result of local socioenvironmental variation.
This study reconstructs the numerological considerations behind a Judeo-Greek innovation in religious terminology, with a focus on its key element—Hellenization of the Hebrew name of God. It demonstrates that the Greek nomen sacrum can also be interpreted as a sacred number, a fact that directly infuses the otherwise broad term κύριος with numinosity. This observation carries multiple implications for understanding the phenomena of nomina sacra and “names-numbers” as well as other related topics, such as the emergence of Greek and Hebrew alphabetic numerals, early Jewish and Christian numeric symbolism, and early binitarian theology.
Polyploidization is known to cause changes in the ploidy levels of plant somatic cells that affect the morphological, physiological and chemical composition. The aim of this research was to investigate the effects of tetraploidization in olive. To do this, several characteristics of 1-year-old shoots of two olive genotypes were compared: the diploid cultivar Leccino (L), and its tetraploid mutant Leccino Compact (LC), considered a slow-growing genotype. LC differed significantly from L in the morphological characteristics, with higher values of diameter, dry mass and volume of the stem (46%, 103%, 102%, respectively), and higher area, mass and volume of the individual leaf (43%, 66%, 73%, respectively). LC also had thicker, longer and wider leaves (30%, 10%, 34%, respectively) and significantly lower leaf density (7%) and lower specific leaf area, leaf mass ratio and leaf area ratio (17%, 4%, 18%, respectively). Internode length and stem density were not significantly different. The results allowed us to thoroughly characterize the effects of tetraploidy on 1-year-old shoots in olive, and also suggest that the slow growth of LC is due to its lower leaf area per unit of total biomass, which reduces leaf area production and, consequently, light interception, resource availability and tree growth. These results will be useful for genetic improvement programmes and for planning further exploitation of tetraploidy in horticulture.
This research reconstructs the business dynamics behind the evolution of the European mutual fund industry, which led Luxembourg to become its main international gateway since the 1960s. We analyze this local industry to understand how political and financial élites influence the economic specialization of small states. We argue that a closely-knit community of local professionals and politicians, well-versed in corporate and European legislation, leveraged the Grand Duchy’s small state status within the nascent European Community to become a financial hub specializing in mutual funds within an emerging network of international financial centers. This position was achieved through bifurcation of sovereignty strategies on the basis of two main premises. First, on the systematic acceptance of conflicts of interest within local financial and political leadership, comprising overlapping roles, revolving-doors, and familial ties in business relationships. Second, on regulatory engineering practices, such as the dynamic interpretation of laws, and the strategic planning of directive assimilation to advance Luxembourg’s interests as opposed to its EU counterparts. The analysis uses archival material from nine archival collections and oral history interviews.
We extend the perceived velocity gradient defined by a group of particles that was previously used to investigate the Lagrangian statistics of fluid turbulence to the study of inertial particle dynamics. Using data from direct numerical simulations, we observe the correlation between the strong compression in the particle phase and the instantaneous local fluid compression. Furthermore, the Lagrangian nature of the particle velocity gradient defined in this way allows an investigation of its evolution along particle trajectories, including the process after the caustic event, or the blow-up of the particle velocity gradient. Observations reveal that, for particles with Stokes number in the range $St \lesssim 1$, inertial particles experience the maximum compression by local fluid before the caustic event. Interestingly, data analyses show that, while the post-caustic process is mainly the relaxation of the particle motion and the particle relaxation time is the relevant time scale for the dynamics, the pre-caustic dynamics is controlled by the fluid–particle interaction and the proper time scale is determined by both the Kolmogorov time and the particle relaxation time.
A quadrotor unmanned aerial vehicle (UAV) must achieve desired flight missions despite internal uncertainties and external disturbances. This paper proposes an adaptive trajectory tracking control method that attenuates unknown uncertainties and disturbances. Although the quadrotor is underactuated, a fully actuated controller is designed using backstepping control. To avoid repeated derivatives of control inputs, a dynamic surface method introduces a filter and auxiliary controller. Lyapunov criteria guide adaptive laws for tuning controller gain and filters. A low-power observer is integrated for state estimation. Additionally, a disturbance observer is developed and combined with the control scheme to handle unknown disturbances. Simulations on a DJI F450 quadrotor demonstrate that the proposed control algorithm offers strong trajectory-tracking performance and system stability under multiple uncertainties and external disturbances during flight.
Many views of moral agency include, implicitly or explicitly, a consciousness requirement—namely, the claim that phenomenal consciousness is a necessary condition of moral agency. This paper casts doubt on the consciousness requirement. I argue that consciousness is not necessary for instantiating four key capacities necessary for moral agency: action, moral concept possession, responsiveness to moral reasons, and moral understanding. I defend my picture of nonconscious moral agency as a plausible account of an entity that can act for moral reasons and can be morally responsible. Lastly, I discuss broader implications of my argument, especially on the possibility of artificial moral agency.
The development of childcare policy can be understood as a process shaped by conflicts across multiple, interconnected dimensions of policymaking. Whilst existing literature often emphasises tensions between established policy legacies and emerging paradigms such as work–family reconciliation and social investment, this study introduces a multi-dimensional framework that includes conflict and negotiation processes between competing policies co-existing within the policy domain but also within policies themselves, emphasising the dynamics of self-reinforcing and self-undermining feedbacks. Our analysis reveals how efforts to resolve tensions in one policy dimension can inadvertently trigger new conflicts in other dimensions. By examining the South Korean case over three decades, we demonstrate how such interwoven tensions drive long-term policy change, offering scholars a more nuanced understanding of the complex mechanisms underlying policy evolution.
This research investigates the spanwise oscillation patterns of turbulent non-premixed flames in a tandem configuration, using both experimental methods and large eddy simulations under cross-airflow conditions. Based on the heat release rate (17.43–34.86 kW) and the burner size (0.15 $\times$ 0.15 m), the flame behaves like both a buoyancy-controlled fire (such as a pool fire) and, due to cross-wind effects, a forced flow-controlled fire. The underlying fire dynamics was modelled by varying the spacing between the square diffusion burners, cross-wind velocity and heat release rate. Two flapping modes, the oscillating and bifurcating modes, were observed in the wake of the downstream diffusion flame. This behaviour depends on the wake of the upstream diffusion flame. As the backflow of the upstream flame moved downstream, the maximum flame width of the downstream flame became broader. The flapping amplitude decreased with a stronger cross-wind. Furthermore, the computational fluid dynamics simulation was performed by FireFOAM based on OpenFOAM v2006 2020 to investigate the flapping mechanism. The simulation captured both modes well. Disagreement of the flapping period on the left and right sides results in the oscillating mode, while an agreement of the flapping period results in the bifurcating mode. Finally, the scaling law expressed the dimensionless maximum flame width with the proposed set of basic dimensional parameters, following observations and interpretation by simulations. The results help prevent the potential hazards of this type of basic fire scenario and are fundamentally significant for studying wind-induced multiple fires.
The rupture of a liquid film, where a thin liquid layer between two other fluids breaks and forms holes, commonly occurs in both natural phenomena and industrial applications. The post-rupture dynamics, from initial hole formation to the complete collapse of the film, are crucial because they govern droplet formation, which plays a significant role in many applications such as disease transmission, aerosol formation, spray drying nanodrugs, oil spill remediation, inkjet printing and spray coating. While single-hole rupture has been extensively studied, the dynamics of multiple-hole ruptures, especially the interactions between neighbouring holes, are less well understood. Here, this study reveals that when two holes ‘meet’ on a curved film, the film evolves into a spinning twisted ribbon before breaking into droplets, distinctly different from what occurs on flat films. We explain the formation and evolution of the spinning twisted ribbon, including its geometry, orbits, corrugations and ligaments, and compare the experimental observations with models. We compare and contrast this phenomena with its counterpart on planar films. While our experiments are based on the multiple-hole ruptures in corona splash, the underlying principles are likely applicable to other systems. This study sheds light on understanding and controlling droplet formation in multiple-hole rupture, improving public health, climate science and various industrial applications.