Order Decay Research Articles

Global order and its enemies

Motivation: A series of crises have demonstrated the low resilience of the global economy to shocks and triggered a discussion about the possible end of globalisation understood as the unrestrained growth of mutual trade and business ties on a global scale. The emerging tendencies to shorten supply chains and block trade as well as calls for an active and strategic trade policy are contributing to the decay of the liberal global order built after World War II. The potential disintegration of the world economy into antagonised blocs and the conflict between the Western model of liberal democracy and autocratic regimes should be considered particularly dangerous. The above phenomena deserve the utmost attention, and the desire to understand them has provided inspiration for taking up this topic.Aim: This study aims to define and interpret the concept of global order in both economic and political dimensions. In this context, two interrelated questions are addressed. The first one is about the character of the global order after World War II and the second one concerns the causes and consequences of its decay.Results: The emerging disintegrative tendencies in the global economy and the anarchisation of international economic relations constitute a negative-sum game. Globalisation has allowed most countries in the world to achieve significant gains in wealth. The benefits that it provides to consumers are too great to be consciously abandoned in favour of an autarkic economic model. Capitalism seems to be able to operate under very different political regimes, hence — with all the differences between political models at the national level — it creates an effective platform for cooperation on the global stage. Nevertheless, the end of the “peace dividend” indicates that effectively preventing the danger of armed conflict by means of economic and military deterrence will be an important part of the future world order.

Dimensional crossover of charge order in IrTe2 with strong interlayer coupling

Tuning dimensionality in van der Waals materials with finite interlayer coupling has introduced various electronic phase transitions by conventional mechanical exfoliation. Particularly when the electronic order is tied to the modulation of the interlayer coupling, such dimensional tunability has a strong impact on its stability and properties, which has rarely been investigated experimentally. Here, we demonstrate a dimensional crossover of charge order in IrTe$_2$ from genuine two- to quasi-three-dimension using low-temperature scanning tunneling microscopy and spectroscopy. Employing atomically thin IrTe$_2$ flakes ranging from monolayer to multilayer, we observe a gradual phase transition of charge order and exponential decay of Coulomb gap with increasing thickness. Moreover, we find a suppression of the density of states emerging at an abrupt lateral interface between two- and three-dimension. These findings are attributed to the interplay between the strongly coupled layers and substrate-driven perturbation, which can provide a new insight into the dimensional crossover of strongly coupled layered materials with hidden electronic phases.

Numerical Solution for Advection-Dispersion Equation with Uniform and Varying Boundary Conditions

In the present study, one-dimensional advection-dispersion equation with variable coefficients is solved numerically with help of PDEPE in a finite porous domain. The pollutant is entering from the left end of the domain along the direction of the flow. Two different types of groundwater velocities have been considered, one rapidly decreasing with position and time and the other one being of sinusoidal nature over position and time. The dispersion coefficient is taken proportional to the groundwater velocity. Transport is included the first order decay and zero-order production parameters being proportional to the exponentially decreasing function with position and time and also being of sinusoidal nature over position and time. The nature of pollutant and porous medium are considered chemically non-reactive. Initially, porous domain is considered not to be solute free. Numerical solutions are obtained for uniform and varying type point sources. In heterogeneous porous media, variations in the parameters of solute transport such as: seepage velocities, dispersion coefficients etc. can be easily deal through numerical models. The effects of various physical parameters on solute concentration profiles are illustrated graphically.

Improved bounds on the gain coefficients for digital nets in prime power base

We study randomized quasi-Monte Carlo integration by scrambled nets. The scrambled net quadrature has long gained its popularity because it is an unbiased estimator of the true integral, allows for a practical error estimation, achieves a high order decay of the variance for smooth functions, and works even for Lp-functions with any p≥1. The variance of the scrambled net quadrature for L2-functions can be evaluated through the set of the so-called gain coefficients.In this paper, based on the system of Walsh functions and the concept of dual nets, we provide improved upper bounds on the gain coefficients for digital nets in general prime power base. Our results explain the known bound by Owen (1997) for Faure sequences, the recently improved bound by Pan and Owen (2022) for digital nets in base 2 (including Sobol' sequences as a special case), and their finding that all the nonzero gain coefficients for digital nets in base 2 must be powers of two, all in a unified way.

A theory of mechanical stress-induced H2O2 signaling waveforms in Planta

Recent progress in nanotechnology-enabled sensors that can be placed inside of living plants has shown that it is possible to relay and record real-time chemical signaling stimulated by various abiotic and biotic stresses. The mathematical form of the resulting local reactive oxygen species (ROS) wave released upon mechanical perturbation of plant leaves appears to be conserved across a large number of species, and produces a distinct waveform from other stresses including light, heat and pathogen-associated molecular pattern (PAMP)-induced stresses. Herein, we develop a quantitative theory of the local ROS signaling waveform resulting from mechanical stress in planta. We show that nonlinear, autocatalytic production and Fickian diffusion of H2O2 followed by first order decay well describes the spatial and temporal properties of the waveform. The reaction-diffusion system is analyzed in terms of a new approximate solution that we introduce for such problems based on a single term logistic function ansatz. The theory is able to describe experimental ROS waveforms and degradation dynamics such that species-dependent dimensionless wave velocities are revealed, corresponding to subtle changes in higher moments of the waveform through an apparently conserved signaling mechanism overall. This theory has utility in potentially decoding other stress signaling waveforms for light, heat and PAMP-induced stresses that are similarly under investigation. The approximate solution may also find use in applied agricultural sensing, facilitating the connection between measured waveform and plant physiology.

Small data global regularity and scattering for 3D Ericksen–Leslie compressible hyperbolic liquid crystal model

We study the Ericksen–Leslie hyperbolic system for compressible liquid crystal model in three spatial dimensions. Global regularity and scattering for small and smooth initial data near equilibrium are proved for the case that the system is a nonlinear coupling of compressible Navier–Stokes equations with wave map to [Formula: see text]. The main strategy relies on an interplay between the control of high order energies and decay estimates, which is based on the idea inspired by the method of space-time resonances. Unlike the incompressible model, the different behaviors of the decay properties of the density and velocity field for compressible fluids at different frequencies play a key role, which is a particular feature of compressible model.

One-loop corrections to the Higgs boson invisible decay in a complex singlet extension of the SM

The search for dark matter (DM) at colliders is founded on the idea of looking for something invisible. There are searches based on production and decay processes where DM may reveal itself as missing energy. If nothing is found, our best tool to constrain the parameter space of many extensions of the Standard Model (SM) with a DM candidate is the Higgs boson. As the measurements of the Higgs couplings become increasingly precise, higher-order corrections will start to play a major role. The tree-level contribution to the invisible decay width provides information about the portal coupling. Higher-order corrections also give us access to other parameters from the dark sector of the Higgs potential that are not present in the tree-level amplitude. In this work we will focus on the complex singlet extension of the SM in the phase with a DM candidate. We calculate the one-loop electroweak corrections to the decay of the Higgs boson into two DM particles. We find that the corrections are stable and of the order of a few percent. The present measurement of the Higgs invisible branching ratio, $\mathrm{BR}(H\ensuremath{\rightarrow}\text{ }\mathrm{invisible})<0.11$, already constrains the parameter space of the model at leading order. We expect that by the end of the LHC the experimental measurement will require the inclusion of the electroweak corrections to the decay in order to match the experimental accuracy. Furthermore, the only competing process, which is direct detection, is shown to have a cross section below the neutrino floor.

Deterministic and stochastic theory for a resonant triad

We study a simple model of three resonantly-interacting nonlinear waves. Linear stability analysis allows for an easy identification of stable and unstable initial conditions. Subsequently, a reformulation of the problem allows us to establish the onset of phase coherence, demonstrating its critical role in the growth of instabilities. Furthermore, we are able to provide explicit expressions for the time-varying moments of the modal amplitudes, as well as for the bispectrum which measures phase coherence. We provide direct insight into the long-time statistics of the system without Monte-Carlo simulation. This includes long-time asymptotics, which show that the system desynchronises, leading to the convergence of the second order moments and decay in the bispectrum.

Seasonal methane emission from municipal solid waste disposal sites in Lagos, Nigeria

The Municipal Solid Waste (MSW) Sector is a major source of Methane (CH4) emission, a Greenhouse Gas (GHG) that contributes to Climate Change. However, governments of developing countries have not been able to address the challenges posed by this sector due to inadequate funding and technical requirement. The objective of this study was to determine how seasonal variation influences the CH4 gas emission. The First Order Decay (FOD) Tier 1 Model was used to estimate CH4 emission from four Solid Waste Disposal Sites (SWDS) in Lagos namely: Ewu-Elepe (Ewu), Abule-Egba (A/E), Soluos (Sol), and Olushosun (Olu) covering the dry and wet seasons, respectively for the inventory year 2020. A known weight of the wet waste deposited was characterized. The study revealed that the Degradable Organic Carbon (DOC) for the dry season was 12.897 GgC/kgWaste while that of the wet season was 12.547 GgC/kgWaste. But, the methane gas generated during the wet season was 0.331 Gg higher than that of the dry season which was 0.134 Gg for the study period. This is an appreciable quantity of methane that can contribute to the global Climate Change impact if not addressed. Therefore, these waste types should be segregated from other recyclables and processed into compost or energy resource.

Investigation of Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) Properties of Dy3+ Doped CaB4O7 Nanoparticles.

CaB4O7 nanoparticles doped with different concentrations of Dy3+ were prepared by using solution combustion method. The recorded Thermoluminescence (TL) and Optically stimulated luminescence (OSL) of CaB4O7:Dy samples for different concentrations of Dy3+ irradiated with 6Gy of X-Ray shows concentration quenching effect above 0.05 at.wt% of Dy3+ concentrations. The TL and OSL kinetic parameters of glow curves were evaluated using "tgcd" and conventional fitting methods. The TL glow curve of the CTB:(0.05%)Dy have five individual glow peaks with maximum peak temperatures at 410, 470, 525, 563 and 593K. TL Dose response of the X-Ray irradiated CTB:(0.05%)Dy is also found to be linear in the range of 1Gy to 50Gy. The OSL glow curves of the CTB:Dy nanoparticles follow non-first order kinetics and can be fitted with the sum of three first order decay curves. Fading characteristics of the TL and OSL signals are studied for 40days and found to be very stable.

Investigation of provincial capacity to produce biogas from waste disposal sites in Turkey

The main aim of this study is to determine the theoretical capacities of waste disposal sites to produce biogas and electricity in Turkey in 81 provinces by using the First Order Decay (FOD) methodology. The population data of each province starting from 1950 to 2020 was used as time series to estimate the best fit model. The same model was also used for the future population estimations until the year 2080. The provinces have different characteristics. The big provinces in Turkey are best fitted with polynomial models. For 38 provinces the best fit models are “third order polynomials”, and for 10 provinces the “second order polynomials” are best fitted. The exponential and linear models are good for 15 and 13 provinces, respectively.Many statistical and “model performance studies” are done for increasing the accuracy level of this study. The results of this study have shown that the best fitted model is acceptable at province level although there are small differences between observed and fitted values.The CH4 emission potential of disposal sites are calculated as 273 thousand tonnes in 1950. This has increased and reached 1.2 million tonnes in 2020. It is projected that it will reach 3.1 million tonnes in 2080. The methane production capacity in Marmara and Central Anatolia regions is calculated as 46% of total capacity. In 2020 these two regions have 1.7 and 0.9 million kW-hr/year electricity production capacity, respectively. The highest provincial capacity of electricity production is observed in İstanbul, Ankara, İzmir, Bursa and Antalya with respective values of 1.02, 0.37, 0.29, 0.20 and 0.16 million kW-hr/year. These top five provinces constitute 37% of Turkey's total capacity.The results of this study have shown that approximately 4.8–7.4% of GHG emissions can be stopped by using CH4 produced in waste disposal sites in energy production. Further usage of methane instead of solid fuels or other non-renewable fuels will decrease the total GHG emissions an extra 2–3.5%. In 2020, 35 million tonnes of CO2 eq. emissions can be reduced in Turkey due to biogas production in waste disposal sites. This is very important from the Climate Change point of view.

Disinfection efficiency prediction under dynamic conditions: Application to peracetic acid disinfection of wastewater

In this work, a mechanistic dynamic model of continuous flow peracetic acid (PAA) disinfection was developed, calibrated and validated, assuming E. coli as indicator microorganism. The model was conceived as a 1-dimensional dispersion model integrating PAA first order decay and E. coli inactivation rate. Lab-scale batch experiments of PAA decay and E. coli inactivation experiments were performed to calibrate corresponding kinetic models. In each sample, conventional wastewater quality parameters were monitored. A PAA pilot reactor was set up to perform both tracer studies, for dispersion model calibration, and continuous flow disinfection experiments, to validate the integration of hydraulics and kinetics models, under both stationary and dynamic conditions. Linear regression models were calibrated to predict hydrodynamic dispersion, given the flow rate, and PAA decay parameters, given effluent quality and PAA dosage. Successful validation of the PAA disinfection model proved the importance of (i) considering the disinfection process as a dynamic system and (ii) integrating real-time estimation of process disturbances, being the initial E. coli concentration and the impact of effluent quality and PAA dosage on PAA decay kinetics. Importantly, novel inactivation models were proposed, as two different modifications of a literature model for thermal inactivation. These models are suitable for dynamic simulation of Eulerian models and can describe the typical triphasic behavior of inactivation kinetics.

Complete Ionization for a Non-autonomous Point Interaction Model in d = 2

We consider the two dimensional Schr\"odinger equation with time dependent delta potential, which represents a model for the dynamics of a quantum particle subject to a point interaction whose strength varies in time. First, we prove global well-posedness of the associated Cauchy problem under general assumptions on the potential and on the initial datum. Then, for a monochromatic periodic potential (which also satisfies a suitable no-resonance condition) we investigate the asymptotic behavior of the survival probability of a bound state of the time-independent problem. Such probability is shown to have a time decay of order $\mathcal{O}(\log t/t)^2$, up to lower order terms.

Anomalous transport for multispecies reactive system with first order decay: time-fractional model

The prediction of pollutant migration and its concentration variation in the subsurface hydrology is vitally requisite for the assessment and restorative treatment of polluted groundwater system. Pollutant migration for the multispecies reactive system cannot be reliably investigated by classical form of convection-dispersion equation (CDE), due to the presence of more than one reactive species. This paper establishes a time-fractional model for multispecies reactive system under the first order sequential reaction network to understand the anomalous or non-Fickian migration phenomenon for reactive pollutants. At present, most of the fractional models are presented for the classical CDE to investigate migration phenomenon for single species system, not for the multispecies reactive system due to the complexity of the modelled framework. The impact of fractional derivative model is analysed for variable dependent migration parameters and constant parameters, both for the multispecies reactive migration phenomenon. The fractional derivative is expressed in the Caputo sense and to handle the non-linearity of problem, Homotopy perturbation method (HPM) is adopted. The advantage of this method, to get the solutions, is that the HPM is independent of small parameters required for the deformation process as used in other existing perturbation techniques, which make it much more convenient to use for non-linear systems. The impact of the fractional derivative index and other migration parameters is graphically depicted for the reactive species and significant influence of fractional term is observed. The derived solutions are then validated by using the corresponding solutions obtained by other existing well-established methods to ensure the convergence of the HPM solutions. As there do not exist any solutions for such fractional models for multispecies reactive system, this study may be advantageous to convey better understanding for the anomalous or non-Fickian migration for reactive pollutants and their remediation planning in the groundwater resources.

Performance analysis of a stormwater green infrastructure model for flow and water quality predictions

Nature-based solutions or Green infrastructure (GI) used for managing stormwater pollution are growing in popularity across the globe. Stormwater GI models are important tools to inform the planning of these systems (type, design, size), in the most efficient and cost-effective manner. MUSIC, an example of such a tool, uses regression and first order decay models. Studies validating MUSIC model performance are, however, scarce, hindering future model development and transferability of the model for systems operating under different design and climatic conditions. To close this gap, this paper evaluates MUSIC for a field scale bioretention system, stormwater wetland and vegetated swale operating under Singapore tropical climate. The treatment modules were able to simulate outflows and effluent pollutant concentrations reasonably well for cumulative event volumes (mostly within ±25%) and cumulative TP and TN loads (within ±30%). Outflow TSS loads were significantly under-estimated as a result of greater variability in measured TSS concentrations across events. The findings indicate that simple empirical models such as MUSIC can be transferred to different regions provided that management decisions are based on long-term modelling efforts. The modules generally simulated the outflow hydrographs and pollutographs of the different inflow and drying/wetting conditions relatively poorly.

Conceptualization of Bioreactor Landfill Approach for Sustainable Waste Management in Karachi, Pakistan

Finding a sustainable approach for municipal solid waste (MSW) management is becoming paramount. However, as with many urban areas in developing countries, the approach applied to MSW management in Karachi is neither environmentally sustainable nor suitable for public health. Due to adoption of an inefficient waste management system, society is paying intangible costs such as damage to public health and environment quality. In order to minimize the environmental impacts and health issues associated with waste management practices, a sustainable waste management and disposal strategy is required. The aim of this paper is to present a concept for the development of new bioreactor landfills for sustainable waste management in Karachi. Furthermore, this paper contributes to estimation of methane (CH4) emissions from waste disposal sites by employing the First Order Decay (FOD) Tier 2 model of the Intergovernmental Panel on Climate Change (IPCC) and determining of the biodegradation rate constant (k) value. The design and operational concept of bioreactor landfills is formulated for the study area, including estimation of land requirement, methane production, power generation, and liquid required for recirculation, along with a preliminary sketch of the proposed bioreactor landfill. This study will be helpful for stockholders, policy makers, and researchers in planning, development, and further research for establishment of bioreactor landfill facilities, particularly in the study area as well as more generally in regions with a similar climate and MSW composition.

Numerical studies on the important fission products for estimating the source term during a severe accident

In this paper, we select important fission products for the estimation of the source term during a severe accident of a PWR. The selection is based on the numerical results obtained from depletion calculations for the typical PWR fuel via the in-house code named DEGETION (Depletion, Generation, and Transmutation of Isotopes on Nuclear Application), release fractions of the fission products derived from NUREG-1465, and effective dose conversion coefficients from ICRP 119. Then, for the selected fission products, we obtain the adjoint solutions of the Bateman equations for radioactive decay in order to determine the importance of precursors producing the aforementioned fission products via radioactive decay, which would provide insights into the assumption used in MACCS 2 for a level 3 PSA analysis in which up to six precursors are considered in the calculations of radioactive decays for the fission product after release from the reactor.

Transverse instability and universal decay of spin spiral order in the Heisenberg model

We analyze the intrinsic stability of spin spiral states in the two-dimensional Heisenberg model isolated from its environment. Our analysis reveals that the SU(2) symmetric point hosts a dynamic instability that is enabled by the existence of energetically favorable transverse deformations---both in real and spin space---of the spiral order. The instability is universal in the sense that it applies to systems with any spin number, spiral wave vector, and spiral amplitude. Unlike the Landau or modulational instabilities which require impurities or periodic potential modulation of an optical lattice, quantum fluctuations alone are sufficient to trigger the transverse instability. We analytically find the most unstable mode and its growth rate, and compare our analysis with phase-space methods. By adding an easy-plane exchange coupling that reduces the Hamiltonian symmetry from SU(2) to U(1), the stability boundary is shown to continuously interpolate between the modulational instability and the transverse instability. This suggests that the transverse instability is an intrinsic mechanism that hinders long-range phase coherence even in the presence of exchange anisotropy.

Suppression of anisotropy of kinetic energy in doped vanadium perovskites by charged defects and spin–orbital polarons

We study the interplay of rotations of t2g-orbitals in vanadium perovskites such as La1−xSrxVO3 induced by spin–orbital polarons and by charged defects. We also analyze the resulting decay of orbital order as well as the suppression of anisotropy of kinetic energy on varying the doping. The strong local correlations and the superexchange interactions are modeled by an extended 3-orbital-flavor Hubbard–Hund model. Because of the charged defects, it is crucial to extend the model by long-range Coulomb defect potentials as well as by long-range electron–electron repulsion. Thereby, the resulting binding of doped holes (i.e., spin–orbital polarons) to negative defects leads to screening by effective dynamic dipoles. The resulting dipolar fields, in combination with disorder, control the defect states and form a soft Coulomb gap inside the Mott–Hubbard gap and thereby control the low-energy properties of the system.

Solution of One-Dimensional Contaminant Flow Problem Incorporating the Zero Order Source Parameter by Method of Eigen-Functions Expansion

A semi – analytical study of a time dependent one – dimensional advection – dispersion equation (ADE) with Neumann homogenous boundary conditions for studying contaminants flow in a homogenous porous media is presented. The governing equation which is a partial differential equation incorporates the advection, hydrodynamic dispersion, first order decay and a zero order source effects in the model formulation. The velocity of the flow was considered exponential in nature. The solution was obtained using Eigen function expansion technique after a suitable transformation. The results which investigate the effect change in the parameters on the concentration was discussed and represented graphically. The study revealed that as the zero order source coefficient increases, the contaminant concentration decreases with time.