Terms Of Moments Research Articles

Convective mesoscale turbulence at very low Prandtl numbers

Horizontally extended turbulent convection, termed mesoscale convection in natural systems, remains a challenge to investigate in both experiments and simulations. This is particularly so for very low molecular Prandtl numbers, such as occur in stellar convection and in the Earth's outer core. The present study reports three-dimensional direct numerical simulations of turbulent Rayleigh–Bénard convection in square boxes of side length $L$ and height $H$ with the aspect ratio $\varGamma =L/H$ of 25, for Prandtl numbers that span almost 4 orders of magnitude, $10^{-3}\le Pr \le 7$ , and Rayleigh numbers $10^5 \le Ra \le 10^7$ , obtained by massively parallel computations on grids of up to $5.36\times 10^{11}$ points. The low end of this $Pr$ -range cannot be accessed in controlled laboratory measurements. We report the essential properties of the flow and their trends with the Rayleigh and Prandtl numbers, in particular, the global transport of momentum and heat – the latter decomposed into convective and diffusive contributions – across the convection layer, mean vertical profiles of the temperature and temperature fluctuations and the kinetic energy and thermal dissipation rates. We also explore the degree to which the turbulence in the bulk of the convection layer resembles classical homogeneous and isotropic turbulence in terms of spectra, increment moments and dissipative anomaly, and find close similarities. Finally, we show that a characteristic scale of the order of the mesoscale seems to saturate to a wavelength of $\lambda \gtrsim 3H$ for $Pr\lesssim 0.005$ . We briefly discuss possible implications of these results for the development of subgrid-scale parameterization of turbulent convection.

Pengaruh Penggunaan Limbah Abu Sekam Padi dan Viscocrete 1003 Terhadap Kuat Tekan dan Kuat Lentur Beton

The purpose of this study was to determine the effect of the use of waste rice husk ash and viscocrete 1003 on the compressive strength and flexural strength of concrete with variations in the mixture of rice husk ash waste 0%, 25%, 30% and viscocrete 1003 0.6%. The results showed that the chemical content of rice husk ash that had been burned was high SiO2 (Silicon Dioxide), which was 75.5 ─ 87.9 % by weight, while the chemical content of unburned rice husk ash was SiO2 (Silicon Dioxide). Which is high that is equal to 86.9 ─ 94.7% by weight. The compressive strength test value of each variation of the specimen which is converted into 28 days of age is for variation 0% the average compressive strength value is 21.590 MPa, for variation 25% with an average compressive strength value of 15.635 MPa and 30% variation with the average compressive strength value is 11.486 MPa. So it can be concluded that the average compressive strength value from the 0% variation to the 25% variation has decreased by 0.05955%, while from the 25% variation to the 30% variation it has decreased by 0.0415%. The flexural strength test value in terms of the maximum average moment on the slab for each variation of the test object converted into 28 days of age is for 0% variation of 146.820 kN.m, for 25% variation of 165.760 Kn.m and variation of 30% of 170.490 Kn.m. So it can be concluded that the average flexural strength value from the 0% variation to the 25% variation has increased by 3.13%, while from the 25% variation to the 30% variation it has increased by 3.36%.

The Description of Important Historical Moments in Terms of Meteorological Aspects

Abstract The purpose of this paper is to present the role of meteorology in certain important historical moments both from the last century and from the present one. To investigate these cases from a meteorological point of view, we used reanalysis data, from some climatological databases, for the events of the last Century and for the events of the 21st Century, we relied on various information that allowed us investigation of the atmosphere, at all levels (synoptic maps at different levels, satellite imaging, backward trajectories, radioactivity data, etc.). Although during the First World War, the investigation of meteorological parameters was limited only to the ground level, in critical moments, the weather forecast decided the fate of some missions carried out on the front during that period. Over time, technology has advanced and the investigation of the atmosphere is carried out on a multitude of levels, using modern investigation technology, with active or passive sensors, located on the ground or on equipment from space. Forecasts have greater accuracy, and information is easily transmitted to the population and institutions of national interest too. In case of natural or anthropogenic disasters, accurate weather forecasts allow quick decisions to be made for the safety of the population. More recently, there are stations (national and international) that also monitor aerosol stratification. The meteorological stations have been modernized and automated, the synoptic maps from the ground and from the altitude are at “one click” away from us. Meteorology has become a field of interest for industry, transport, military and, last but not least, for the safety and security of the general population. In this paper we will show the progress in this field of activity and the implications in people’s everyday life.

Systematization of an Educational Experience of Social Appropriation of Science, Technology and Innovation:The Collective Memory built with Participatory Virtual Tools

The objective of this research was to construct the collective memory of a socio-educational intervention process from the perspective of the different educational actors, students, teachers, and community leaders. For this purpose, a critical epistemological approach was used, a qualitative methodology within the framework of the approach of systematization of experiences and methods of construction of collective memory such as timelines. This methodology was developed in the context of a pandemic during the year 2020 and required adaptations in the instruments and forms of data collection. Findings show the significance of collective experience in terms of moments of reception of physical spaces and elements for the development of science, technology and innovation, as well as the importance of participation in local processes of identification and solution of their own problems, and the relevance of work in and with the community.

Geometry-modulated dipole polarizability of the two-dimensional Mott-Wannier excitons in gate-defined anisotropic quantum dot

A theoretical investigation on neutral excitons confined to a mono-layer (ML) semiconductor transition metal dichalcogenide (TMDC) materials under the influence of elliptically deformed gate induced confining potential is presented. It has been shown that the anisotropy of the confinement induces the anisotropy of linear response of the system on in-plane external electric field. The linear response is expressed in terms of principal moments of the static dipole polarizability tensor. In this manner the direction-dependent polarizability of the system can be fully controlled by tuning the parameters of gate-induced confining potential. The components of the polarizability tensor are determined using finite-field method based on the exact diagonalization of the electron-hole Hamiltonian including confining potential, Coulomb electron-hole interaction and an external electric field, within effective mass approximation, close to the K-points of the first Brillouin zone of a single-layer MX_2 material. The useful scaling relations for energies and dipole polarizabilities as functions of material parameters have been found. The influence of the anisotropy of the confining potential on correlated behavior of charge distribution inside the neutral system has also been demonstrated.

Celestial insights into the S-matrix bootstrap

We consider 2-2 scattering in four spacetime dimensions in Celestial variables. Using the crossing symmetric dispersion relation (CSDR), we recast the Celestial amplitudes in terms of crossing symmetric partial waves. These partial waves have spurious singularities in the complex Celestial variable, which need to be removed in local theories. The locality constraints (null constraints) admit closed form expressions, which lead to novel bounds on partial wave moments. These bounds allow us to quantify the degree of low spin dominance(LSD) for scalar theories. We study a new kind of positivity that seems to be present in a wide class of theories. We prove that this positivity arises only in theories with a spin-0 dominance. The crossing symmetric partial waves with spurious singularities removed, dubbed as Feynman blocks, have remarkable properties in the Celestial variable, namely typically realness, in the sense of Geometric Function Theory (GFT). Using GFT techniques we derive non-projective bounds on Wilson coefficients in terms of partial wave moments.

Quantum separability criteria based on realignment moments

Quantum entanglement is the core resource in quantum information processing and quantum computing. It is a significant challenge to effectively characterize the entanglement of quantum states. Recently, elegant separability criterion is presented by Elben et al. (Phys Rev Lett 125:200501, 2020) based on the first three partially transposed (PT) moments of density matrices. Then, Yu et al. (Phys Rev Lett 127:060504, 2021) proposed two general powerful criteria based on the PT moments. In this paper, based on the realignment operations of matrices we propose entanglement detection criteria in terms of such realignment moments. We show by detailed example that the realignment moments can also be used to identify quantum entanglement.

Economic policy uncertainty and industry risk on China’s stock market

We propose a dynamic mixture Copula with time-varying weight, which is endowed with generalized autoregressive score dynamics. Based on this model, we portray the lower-tail dependence between the return of WIND first-level industry and CSI-300 index as a proxy variable for the industry risk in China’s stock market, and use the VAR-GARCH-in-mean model based on BEKK-GARCH to deconstruct the different impact of the economic policy uncertainty (EPU) on industry risk of the first and second moments in terms of four policy categories, namely fiscal policy, monetary policy, trade policy, and foreign exchange rate and capital account policy. The results are followed. Firstly, the risk of Consumer Discretionary is averagely the highest, while the risk of Utilities remains the lowest. Secondly, category-specific EPU has no significant mean spillover to the risk of overall industries, while the variance spillover is significant for all the cases. Thirdly, except for Real Estate, the GARCH-in-mean effect is not significant of EPU on industry risks. Further more, all those three kinds of impact show industrial heterogeneities. To avoid systemic risks, we advise that the issue of economic policy should be forward-looking, consistent, and targeted, especially for sensitive industries.

Characteristic polynomials of random truncations: Moments, duality and asymptotics

We study moments of characteristic polynomials of truncated Haar distributed matrices from the three classical compact groups [Formula: see text], [Formula: see text] and [Formula: see text]. For finite matrix size we calculate the moments in terms of hypergeometric functions of matrix argument and give explicit integral representations highlighting the duality between the moment and the matrix size as well as the duality between the orthogonal and symplectic cases. Asymptotic expansions in strong and weak non-unitarity regimes are obtained. Using the connection to matrix hypergeometric functions, we establish limit theorems for the log-modulus of the characteristic polynomial evaluated on the unit circle.

Effect of the Looseness of the Beam End Connection Used for the Pallet Racking Storage Systems, on the Mechanical Behavior of the Bearing Beams.

The worldwide use of pallet racking storage systems leads to the necessity for research regarding the effects of the clearance between the metallic tabs of the connector and upright slots (looseness effect) on the performance of load-bearing beams. Firstly, the looseness angle and the rotational stiffness were experimentally obtained for three types of beam-to-upright connections. A theoretical approach is used to investigate the magnitude of the looseness effects that occurred on the performances of the bearing beam of the pallet storage systems in terms of the bending moment developed at the midpoint of the beam and maximum deflection. Calculation corrections were evaluated for the connections involved in the experimental part, for the case which considers the looseness effects with respect to the case which does not consider the looseness effect. In order to evaluate the effects of the parameters of the connections on calculus corrections, the theoretical model was used for other types of beam-to-upright connections. It is shown that the maximum corrections are 2.99% and 5.16% for the bending moment developed at the midpoint of the beam and for the maximum deflection, respectively. It is proved that the connector type affects the size of the correction.

Two-scale off-and online approaches to geometrically exact elastoplastic rods

This work compares two different computational approaches to geometrically exact elastoplastic rods. The first approach applies an elastoplastic constitutive model in terms of stress resultants, i.e. forces and moments. It requires knowledge of the rod’s elasticity and yield-criterion in terms of stress resultants. Furthermore a resultant-type hardening expression must be formulated. These are obtained by integrating elastoplastic stress and hardening measures from three-dimensional continuum mechanics over the rod’s deformed cross-section, which is performed in an offline stage. The second approach applies an FE ^2 approach as established in computational homogenization. Therein, the macro-scale describing the geometrically exact rod is coupled to the micro-scale, i.e., the cross-section of the rod. A novelty of the presented work is the determination of a hardening tensor for use in the stress resultant approach. The mechanical response of both approaches is first compared on the material point level, a single cross-section of a uniformly strained rod. Later, also the mechanical response and the deformation of finitely and non-uniformly strained rods are investigated.

A look at the theoretical analysis of "Azerbaijan rengleri" and "Rast deramedi" in the works of Ramiz Zohrabov

Teqdim olunan meqalede görkemli musiqişünas-alim, Azerbaycan Respublikasının xalq artisti, senetşünaslıq üzre elmler doktoru, professor Ramiz Zöhrabovun “Azerbaycan rengleri” haqqında elmi-tedqiqat eserinin xüsusiyyetleri tedqiq edilmişdir. Melumdur ki, professor Ramiz Zöhrabov xalq musiqi yaradıcılığının araşdırılması istiqametinde bir çox elmi eserlerin müellifidir ve musiqişünasın “Azerbaycan rengleri” adlı kitabı da şifahi eneneli Azerbaycan professional musiqisinin esas janrları ile bağlıdır. Meqalede Azerbaycan renglerinin janr, lad-meqam ve melodik xüsusiyyetlerin tedqiqi meseleleri esas götürülmüşdür. Bundan ireli gelerek meqalede esas meqsed kimi vurğulanmışdır ki, R.Zöhrabov Azerbaycan renglerini şifahi eneneli Azerbaycan professional musiqisinin bir esas janrı kimi seciyyelendirmiş ve onların xüsusiyyetlerini elmi-nezeri aspektden araşdırmışdır. Onu da qeyd edek ki, müasir Azerbaycan musiqişünaslığında reng ve onun janrlarının tedqiqi meseleleri mehdud saydadır. Meqalede R.Zöhrabovun Azerbaycan renglerinin araşdırılması ile bağlı müddeaları tedqiq edilmiş ve esas prinsipleri işıqlandırılmışdır. Xüsusile bu janrın növleri olan diringi ve deramedin quruluş xüsusiyyetlerinin etraflı tedqiqi gosterilmisdir. Meqalenin metodologiyası nezeri ve tarixi melumatlara esaslanmış ve ireli sürülen fikirler müqayiseli şekilde etraflı tedqiq edilmişdir. Eyni zamanda R.Zöhrabovun yaradıcılığına istinaden “Rast deramedi”nin nezeri esaslarının tehlili meqam, melodik xüsusiyyetler, musiqi forması ve diger cehetler baxımından tehlile celb edilmişdir. Meqalede ilk defe olaraq, R.Zöhrabovun “Azerbaycan rengleri” adlı elmi-tedqiqat eserindeki ireli sürdüyü müddealar kompleks şekilde araşdırılmışdır. Bu zaman “Rast deramedi”nin nezeri cehetden tehlili xüsusile vurğulanmış ve lad-meqam esası ile melodik xüsusiyyetleri nezere çatdırılmışdır. Bele neticeye gelinmişdir ki, professor R.Zöhrabovun bu kitabı Azerbaycan renglerinin seciyyevi janr xüsusiyyetlerinin araşdırılması istiqametinde mühüm ehemiyyet kesb edir.

Constitutional moments and resurgent citizenship

ABSTRACT Citizenship can be seen as successive moments of heightened consciousness about belonging. Contests over citizenship in the contemporary world may be construed in terms of a constitutional moment which has transformed the Constitution into an ‘insurgent’ text – recasting the constitutional order from a fetter on democracy to one of re-iteration of the principles that were adopted by ‘We, the people’. The resurgent ‘people’ have claimed the power to ‘launch something unprecedented’ by recalling the constitutional moment. A range of innovative protests in India have inserted new idioms of constitutional citizenship through rallies and sit-ins, street art, and theatre, asking for a democratic conversation on the constitution and law. These iterations have led to a resurgence of citizenship by making the Constitution popular.

Moment constraints in beams with discrete and continuous rotational symmetry

This study presents a general analysis of how the transverse rotational symmetry of a beam imposes equality constraints among transverse beam moments. Efficient analytic methods are developed to derive symmetry-imposed constraints among $k$th order moments in beams with continuous or $n$-fold rotational symmetry for arbitrary $k$ and $n$. The formalism also enables one to construct symmetry arguments based on how discrete and continuous rotational symmetries manifest themselves differently in terms of beam moments. Three case studies on beams with continuous, twofold, and threefold rotational symmetries are conducted. We prove that, regardless of their triangulation, beams with threefold rotational symmetry (e.g., from electron cyclotron resonance ion source) always have the same rms properties as beams with cylindrical symmetry. These counterintuitive results derived purely from symmetry considerations have clarified beam dynamics at the Facility for Rare Isotope Beams.

The effect of dynamic load on tall building

In this study, the effectiveness of the structure of a tall building (consisting of nineteen floors) was analysed and investigated by the existence or absence of shear walls (SW) to resist loads of wind and earthquake effect. Note that each floor contains four apartments comes under zone 2 Four different styles of shear walls were used in terms of shape and location. The results were analysed and discussed for each case and for each floor, and comparisons were made between those results in terms of (moments, lateral forces, vertical loads, and torsion moments). There are several techniques for solving structural engineering problems, and one of those distinct techniques is the design optimization techniques method. The most complicated high-rise buildings that use design optimization, which includes each of size and topological optimization, are addressed by considering stability, safety, and responsiveness to various sorts of loadings A project includes wall-frame structural optimization. When this wall and core system was subjected to various loadings, it was tested for displacement, internal stresses, and intensities. The SAP2000 Software has made design improvements to the construction of the reinforced concrete plane frame to minimize the costs to beams and columns of the concrete and steel by Using a computer model called an Artificial Neural Network (ANN). The concept method is in accordance with ACI-318-08 Code. To improve the design optimization, many variables have been used depth, width, and the steel reinforcing area Including both (longitudinal and shear reinforcement). It can be concluded that by putting the shear walls nearest the structure geometric center the best performance of seismically loaded structure can be achieved; the maximum displacement, bending moment horizontal forced, and torsional moments were decreased.

Large Vertical Piezoelectricity in a Janus Cr2I3F3 Monolayer.

Two-dimensional (2D) materials have potential applications in nanoscale sensors and spintronic devices. Herein, motivated by experimental synthesis of a CrI monolayer possessing intrinsic magnetism and a Janus MoSSe monolayer with piezoelectricity, we propose a 2D Janus CrIF monolayer as a multifunctional material exhibiting both piezoelectricity and ferromagnetism. Using density functional theory calculations, we systematically investigated the structural stability and the electronic, magnetic, and piezoelectric properties of the Janus CrIF monolayer. We predicted that a vertical polarization of up to −0.155 × 10 C/m is induced in the CrIF monolayer due to the breaking of symmetry. The origination mechanism of polarization was demonstrated in terms of a local dipole moment calculated by maximally localized Wannier functions. Meanwhile, it was found that a remarkable piezoelectric response can be produced under a uniaxial strain in the basal plane. The calculated piezoelectric coefficients of the CrIF monolayer compare favorably with those of the frequently used bulk piezoelectric materials such as –quartz and wurtzite AlN. Particularly, the e and d values of the CrIF monolayer are nearly 10 times as large as that of Mo-based transition metal dichalcogenides. We also found that the magnitude of e mainly arises from the ionic contribution, while the electronic contribution can be nearly neglected. The considerable piezoelectric response combined with the intrinsic magnetism make the Janus CrIF monolayer a potential candidate for novel multifunctional devices integrating both piezoelectric and spintronic applications.

자유항주모형시험과 회귀분석을 통한 선체 동역학 모델의 개발

The present study suggests a procedure of establishing a ship dynamics modeling by regression of free-running model test results. The hydrodynamic force and moment of the whole model ship is derived from the low-pass filtered acceleration in the turning circle and zigzag maneuver tests. Force and moment of the propeller and rudder are separated from that of the whole ship to acquire the hull force and moment terms, based on the principles of the component model. The low-pass filter frequency is verified in prior to dynamics modeling, to find the threshold frequency of 2.5 Hz. The dynamics modeling of the hull is compared with the component modeling by captive model tests. Because of strong correlation between sway velocity, yaw angular velocity, and heel angle, each maneuvering coefficient is not able to be validated, but the whole modeling shows good agreement with the captive model tests.

Evaluation of root lodging resistance during whole growth stage at the plant level in maize

Root lodging due to strong storm wind is a common problem in maize (Zea mays) production, leading to reduced crop yield and quality and harvest efficiency. Little information is available on quantifying effects of vertical leaf area distribution on root lodging in crops such as maize. Anti-lodging index of root was computed by the formula: ALroot = Mroot / Mwind, where AL denotes anti-lodging index, and M moment of force. Mroot, root failure moment of force equals to moment arm times max root side-pulling force measured in situ by means of the digital pole dynamometer, and Mwind, wind resultant moment of force is estimated with vertical leaf area distribution and wind speed. Two maize cultivars were examined at 5 different growth stages from V8 to physiological maturity in 2019 and 2020, in Qingdao, China. Root anti-lodging index in tested cultivars fluctuated to a small extent within any year during whole growth period excluding at V8, while there was an inter-annual shift in index means (1.23 vs 0.84). Both root failure moment and wind resultant moment increased first and then decreased with the growth stage, and their influences on root anti-lodging index varied with the year. At wind grade 6, effect sizes, as contribution to root anti-lodging index, of root moment and wind moment were respectively 0.88 and 0.98. The difference in anti-lodging index between cultivars seemed to be disappearing as wind grade goes up. Root failure moment of force positively related to single root tensile resistance, root-soil ball volume, root number and total root length, whose correlation coefficient was the maximum of 0.94. Root anti-lodging index of maize proved stable from V8 on during whole growth period, and vertical leaf area distribution played a substantial role in maize root lodging in terms of wind resultant moment. Our findings provide the insights into root lodging events in crops such as maize, and would serve an approach to assessing crop root lodging resistance in breeding and cultivation programs.

Influence of the P-delta Effect and Stiffness Irregularity on the Structural Behavior of Reinforced Concrete Buildings

In this research, the influence of the stiffness irregularity and the p-delta effect on the structural behavior of a reinforced concrete building is analyzed. The main objective is to determine the impact of the stiffness irregularity and the p-delta effect on the structural behavior in regular and irregular buildings. First, the linear dynamic analysis procedure is performed in order to determine the structural response in terms of drifts, shear force and moments per floor. Subsequently, we proceed with the nonlinear static analysis procedure to obtain the capacity curve of the structure. The post elastic stiffness and the overall ductility of the structure are determined from the capacity curve. Finally, a comparative analysis of the responses from the linear and nonlinear analysis is carried out to determine the percentage variation of the results. When analyzing the structures that consider the stiffness irregularity and the p-delta effect, variations of up to 16.50%, 11.00% and 14.00% have been obtained in drifts, shear force and moments per floor respectively, which are considerable values. When the p-delta effect is considered in structures with the presence of stiffness irregularity, there is a variation in stiffness of up to 59.85%. With this result it is explained that the p-delta effect produces a greater degradation of the overall stiffness of the structure.

The Collector, the Glitcher, and the Denkbilder: Toward a Critical Aesthetic Theory of Video Games

To examine the aesthetics of video games, this paper proposes to consider games as a contemporary multi-media version of the so-called “Denkbild,” or “thought-image,” an experimental genre of philosophical writing employed by members of the Frankfurt School that takes literary snapshots of philosophical, political, and cultural insights that interrupt and challenge the enigmatic form of traditional philosophical thinking. While previous scholarship tends to examine the aesthetics of video game as a homogenous, self-contained genre that can be clearly defined and understood within the framework of a variety of dichotomies, thinking of video game through the lens of the Denkbild allows us to understand the diversity, conditionality, and incommensurability of game as a multimedia aesthetic object. By presenting two snapshots of video game players, the collector and the glitcher, this paper argues that the concept of Denkbild allows us to better understand the relationships between game, gamers, and the socio-political context in terms of unexpected bonds, accidental breakthroughs, and moments of absolute freedom.