Power Tail Research Articles

Controllable multi-stable-state operation in an AOM actively Q-switched all-fiber laser system.

This paper presents a comprehensive experimental study of multi-stable-state output characteristics in an all-fiber laser with an acoustic-optical modulator (AOM) as the Q-switcher. For the first time, in this structure, the partitioning of the pulsed output characteristics is explored, dividing the operating status of the laser system into four zones. The output characteristics, the application prospects, and the parameter setting rules for working in stable zones are presented. In the second stable zone, a peak power of 4.68 kW with 24 ns was obtained at 10 kHz. This is the narrowest pulse duration achieved with an AOM actively Q-switched all-fiber linear structure. The pulse narrowing is attributed to the rapid release of signal power and pulse tail truncated by AOM shutdown.

Validation of the Griffin application for TREAT transient modeling and simulation

The Transient Reactor Test Facility (TREAT) at Idaho National Laboratory is a graphite-moderated, air-cooled facility that was restarted in 2018 and is specifically built to conduct transient reactor tests. The Department of Energy focused modeling and simulation efforts between 2015 and 2019 on obtaining multiphysics solutions using the Griffin reactor physics application. This research has: (1) developed a consistent analysis method that automatically maps the neutronics data generated with Serpent onto the Griffin model, (2) improved the predictive capability of the traditional MCNP and Point Kinetics models that are commonly used in TREAT modeling and the preparation of engineering calculations, (3) determined the average recoverable energy in TREAT fuel per fission event, and (4) calculated a dynamic energy coupling factor that demonstrates the dependency of the energy deposition in the experiments during transients. Three experiments conducted in 2018 form the basis for the validation of Griffin for the transient modeling of TREAT. The first two experiments are 1.5% and 2.6% Δk/k transient prescription experiments with flux wires placed in the M8CAL test rig. The third experiment is a 0.6% Δk/k with the Minimal Activation Retrievable Capsule Holder (MARCH) test rig and the Separate Effect Test Holder (SETH) capsule, a light-water reactor rodlet in dry conditions. The core behavior predicted by Griffin for the transient prescription transients agrees well with the measured core power, peak power, and reactor feedback. The exception is the total energy deposition, which is underpredicted. The core behavior for the MARCH-SETH transient is significantly influenced by delayed neutrons since the reactivity insertion is delayed critical (i.e. ρ<βeff). The Griffin model experiences a stronger temperature feedback, leading to a lower peak power and total energy deposition. Increasing the number of temperature tabulation points significantly improves the solution for the MARCH-SETH transient. In addition, updating the 1.5% Δk/k transient model to ENDF/B-VIII.r0 data resolves the discrepancy in the prediction of the power tail and the total energy deposition. This is attributed to the new graphite S(α,β) data, which leads to lower values of the temperature coefficient of reactivity. The predicted energy coupling factors in both wire and rodlet experiments is the paramount parameter for TREAT modeling and simulation. In both cases, the Griffin predictions compare very well with measured values and exhibit consistent behavior, which is not observed in MCNP predictions. This work shows that Griffin is able to resolve the time-dependent effects from the control rod movement and the core heat-up in both the core and experiments.

Analysis of Low Power and High Speed Double Tail Comparator Using Gnrfet Technology

Moore’s guideline has been a fundamental benchmark for patterns in the locale of microelectronics and measurements preparing. It has played an instrumental position in driving the part financial aspects and downsizing of the component time frame has been the major system for improving the general execution of the gadget. in any case, as we hold to diminish, close to the nanometre routine, various elements like line region unpleasantness, burrowing outcomes, arbitrary dopant changes, fast channel results, and numerous others have a tendency to impact its working and thereupon, its rise as of intense quintessence to investigate other open door substances that may help intensify the soaking Moore’s guideline. some of the research is as of now going inside the zone and numerous open door advances like CNFETs, FINFETs, GNRFETs. Region sway transistors the utilization of Graphene Nano-Ribbons (GNRFETs) has developed as promising innovation as a result of their stunning supplier transport homes and capacity for huge scale preparing and creation. This paper investigates the GNRFETs inverter generally speaking execution with CMOS inverter at 32nm time hub. Reproductions recommend about 2.5x upgrades inside the proliferation dispense with and 2x enhancements inside the quality put-off item (PDP). what’s more improvement of results was gotten through different the kind of Nano-Ribbons together with the convey voltage. On different the broad kind of nano-ribbons, it has turned out to be set that, spread put off reductions, at the indistinguishable time as powerful power utilization will increment. principally based definitely at the derivation, the upgraded outcome altered into chose to be 15 nano-ribbon. The outcomes imply that that GNRFET is a promising open door for Si-CMOS, making it a splendid recommendation to help intensify soaking Moore’s law. Graphene is an exciting new fabric with radiant electric properties, for the most part inside the state of graphene nanoribbons. on this educational document, we inspect steel-oxide-semiconductor and graphene nanoribbon discipline- impact transistors and recommend the proceeded with utilization of MOSFETs through 2023. This archive fills in as a top-notch initial texture for people with a legacy in semiconductors who want to find out about graphene and GNRFETs.

Retracted: Peak to average power ratio reduction of ZT DFT‐S‐OFDM signals using hybrid improved monarch butterfly optimization‐PTS scheme with TR‐clipping scheme

SummaryCurrent research on zero‐tail discrete Fourier transform spread OFDM, an add on to conventional discrete Fourier transform DFT‐OFDM modulation without cyclic prefix (CP). Its low power tail is configured for coping up with channel's delay spread. Advantageous feature of ZT DFT‐S‐OFDM has drawn researchers for deploying it as a potential waveform candidate to fifth generation (5G). However, the intrinsic shortcoming of high peak to average power ratio (PAPR) should be alleviated. In order to improve that work, we propose a hybrid PAPR scheme that implements optimized partial transmit sequence (PTS) with tone reservation (TR) with clipping technique. Its earlier work stresses for reducing PTS scheme's computational complexity with enhanced version of monarch butterfly optimization (MBO) for PAPR reduction in ZT DFT‐S‐OFDM system. The proposed model reduced the correlation among the candidate signals. In this paper, we further reduce PAPR by deploying TR clipping pair, which reduces the influence of clipping noise and decreases ZT DFT‐S‐OFDM signal's PAPR at same time. The proposed hybrid technique produces excellent PAPR reduction while improving receiver sensitivity and effective throughout. The performance comparison is done using the parameters like PAPR and BER to confirm that this introduced design exceeds current waveforms designs with more economical design structure.

Invariance and attraction properties of Galton–Watson trees

We give a description of invariants and attractors of the critical and subcritical Galton–Watson tree measures under the operation of Horton pruning (cutting tree leaves with subsequent series reduction). Under a regularity condition, the class of invariant measures consists of the critical binary Galton–Watson tree and a one-parameter family of critical Galton–Watson trees with offspring distribution {qk} that has a power tail qk∼Ck−(1+1/q0), where q0∈(1/2,1). Each invariant measure has a non-empty domain of attraction under consecutive Horton pruning, specified by the tail behavior of the initial Galton–Watson offspring distribution. The invariant measures satisfy the Toeplitz property for the Tokunaga coefficients and obey the Horton law with exponent R=(1−q0)−1/q0.

Collective Dynamics Inside Paul Trap With Stray Electric Field Using Nonextensive Distribution Function

The collective dynamics of a collision-less nonneutral plasma is analyzed in the presence of stray electric field inside a Paul trap. Experiments in Paul traps have indicated the presence of power tail distribution functions. Therefore, a Tsallis distribution function represents the initial distribution of charged particles inside the trap. The stroboscopic map in phase space reveals a closed curve, indicating that a carefully chosen initial distribution function will yield a time-periodic distribution function. The time-averaged distribution function is doubled humped indicating instabilities. The position of the double hump and the asymmetry in the spatial variation of temperature inside the trap depends on the magnitude and the orientation of the stray electric field inside the trap.

The first passage problem for stable linear delay equations perturbed by power law Lévy noise.

This article studies a linear scalar delay differential equation subject to small multiplicative power tail Lévy noise. We solve the first passage (the Kramers) problem with probabilistic methods and discover an asymptotic loss of memory in this non-Markovian system. Furthermore, the mean exit time increases with the power of the small noise amplitude, whereas the prefactor accounts for memory effects. In particular, we discover a nonlinear delay-induced exit acceleration due to a non-normal growth phenomenon. Our results are illustrated by the example of a linear delay oscillator driven by α-stable Lévy flights.

Combined influence of Urbach’s tail width energy and mobility of charge carriers on the photovoltaic performance of bulk heterojunction organic solar cells

Bulk heterojunction organic solar cells with four different Urbach’s tail width energies ( $${E}_{U}$$ ) are simulated, and the combined influence of $${E}_{U}$$ and charge carrier mobility on the short circuit current ( $${J}_{sc})$$ , open circuit voltage ( $${V}_{oc})$$ , fill factor (FF), power conversion efficiency (PCE), Langevin and tail state recombination is investigated. The results show that $${J}_{sc}$$ decreases more drastically with increasing $${E}_{U}$$ in the lower mobility range and then asymptotically converges to a single value in the large mobility range. Likewise, with the increase in mobility, $${V}_{oc}$$ decreases nearly linearly with different slopes depending on different $${E}_{U}$$ in the lower mobility range and then different slopes converge to a single slope in the larger mobility range. Thus, $${V}_{oc}$$ becomes $${E}_{U}$$ independent in the higher mobility range. Furthermore, it is found that by increasing $${E}_{U}$$ , the maximum values of FF and PCE shift towards the higher mobility range. It is shown that the influence of combined optimization of $${E}_{U}$$ and mobility enhances both FF and PCE, but its effect on FF is much more significant than that on PCE.

OQAM-OFDM for Wireless Communications in Future Internet of Things: A Survey on Key Technologies and Challenges

In this survey paper, we focus on the offset quadrature amplitude modulation-based orthogonal frequency division multiplexing (OQAM-OFDM)-based wireless communications in future Internet of Things (IoT). First, we present the OQAM-OFDM-based wireless communication system model for IoT and show its superiority compared with OFDM. Then, we give a survey and analyze key technologies including the prototype filter design, peak to average power ratio reduction, tail reduction, channel estimation, and multiple-input multiple-output combination in OQAM-OFDM-based wireless communication systems for IoT. Extensive simulations are conducted to verify the spectral superiority of OQAM-OFDM and compare the corresponding performances of OQAM-OFDM with OFDM in the above key technology areas.

Comprehensive Analysis of a Coaxial Ultralight Rotorcraft and Validation with Full-Scale Flight-Test Data

The results of full-scale flight testing in combination with comprehensive analysis of an ultralight counterrotating coaxial rotorcraft are presented. The CoAX 2D was developed and manufactured by edm aerotec in Geisleden, Germany. The helicopter features two-bladed, 6.5-m-diameter upper and lower rotors in teeter configuration with uniform airfoil sections and linearly twisted blades. The focus was on the development of a comprehensive analysis model using CAMRAD II, its validation with measured flight-test data, and results evaluation from both measurements and analysis. The CoAX 2D's power consumption, tail loads, hub loads, teeter angles, and blade-tip clearance were evaluated for both hover and forward flight. Performance and thrust correlated well between the analysis and the measurements. Effects from rotor-fuselage interference dominated the measured 2/rev hub load and 1/rev teeter angle harmonics. The numerical model also matched well with the measured vibrations during forward flight in terms of hub loads, teeter angles, and resulting blade-tip clearance. Minimal rotor-rotor blade-tip clearance occurred at low flight speeds because of dominating effects from rotor-rotor interference.

Quantitative estimates for the flux of TASEP with dilute site disorder

We prove that the flux function of the totally asymmetric simple exclusion process (TASEP) with site disorder exhibits a flat segment for sufficiently dilute disorder. For high dilution, we obtain an accurate description of the flux. The result is established under a decay assumption of the maximum current in finite boxes, which is implied in particular by a sufficiently slow power tail assumption on the disorder distribution near its minimum. To circumvent the absence of explicit invariant measures, we use an original renormalization procedure and some ideas inspired by homogenization.

Coupling of statistics and math models identifies power tail jump patterns in time series

Researchers provide a framework that accounts for the proximity of nonlinear models with power tail jumps to time series.

How close are time series to power tail Lévy diffusions?

This article presents a new and easily implementable method to quantify the so-called coupling distance between the law of a time series and the law of a differential equation driven by Markovian additive jump noise with heavy-tailed jumps, such as α-stable Lévy flights. Coupling distances measure the proximity of the empirical law of the tails of the jump increments and a given power law distribution. In particular, they yield an upper bound for the distance of the respective laws on path space. We prove rates of convergence comparable to the rates of the central limit theorem which are confirmed by numerical simulations. Our method applied to a paleoclimate time series of glacial climate variability confirms its heavy tail behavior. In addition, this approach gives evidence for heavy tails in datasets of precipitable water vapor of the Western Tropical Pacific.

Enabling Water-Energy–Food Nexus: A New Approach for Sustainable Agriculture and Food Security in Mountainous Landlocked Countries

Majority of landlocked mountainous countries are poorly ranked in Human Development Index (HDI), mostly due to poor per capita agriculture production, increasing population, unemployment, expensive and delayed transportation including several other factors. Generally, economy of such countries substantially relies on subsistence agriculture, tourism, hydropower and largely on remittance etc. Recently, it has been argued that to utilize scarce suitable land efficiently for food production, poor inland transport, hydropower, irrigation, drinking water in integration with other developmental infrastructures, an overarching policy linking water - energy – food nexus within a country for combating water, energy and food security would be most relevant. Thus, in present paper it has been opined that promotion of such linkage via nexus approach is the key to sustainable development of landlocked mountainous countries. Major land mass in mountainous countries like Nepal remains unsuitable for agriculture, road and other infrastructure profoundly imposing food, nutrition and energy security. However, large pristine snowy mountains function as wildlife sanctuaries, pastures, watershed, recharge areas for regional and global water, food and energy security. In return, landlocked mountainous countries are offered certain international leverages. For more judicious trade off, it is recommended that specific countries aerial coverage of mountains would be more appropriate basis for such leverages. Moreover, for sustainability of mountainous countries an integrated approach enabling water - energy – food nexus via watershed-hydropower-irrigation-aquaculture-agriculture-integrated linking policy model is proposed. This model would enable protection of watershed for pico, micro, and mega hydro power plants and tail waters to be used for aquaculture or irrigation or drinking water purposes for food and nutrition security.

Income distribution and income shares: wealth and income distributions explained using generalised Lotka-Volterra SFC ABM models

This paper combines a classical approach to economics with standard finance theory in a Lotka-Volterra framework. The models are agent-based, general Lotka-Volterra (GLV) models, using very simple homogeneous or heterogeneous agents. The agents are owners of capital, they receive wages and returns on their capital, and spend a portion of their wealth on consumption. As such the models use realistic economic variables. The models give simple outputs of ‘log-normal’-like bodies and power tail distributions for both wealth and income. These distributions match those seen in real economies. The models are unique in giving real world distributions from a statistical mechanical model that uses absolutely identical agents. The models demonstrate that wealth and income inequality is driven by the economic force of concentration of capital through a statistical-mechanical wealth condensation process. The models also show a direct relationship between the macroeconomic labour share of income and the distributions of personal wealth and income. In addition, the models give a proposed ‘compulsory saving’ regime that appears highly effective for the reduction of poverty.

Exponential tails of drug disposition curves: Reality or appearance?

Since plasma drug concentration-time curves, C(t), can be examined only over a limited time range, it is unclear whether they have an exponential or power-law tail. An answer to this question is important because of the necessary extrapolation beyond the observation period (to infinity). Based on renewal theory, the present analysis shows that due to the recirculation process drug disposition curves become exponentially tailed also when the underlying organ transit time distributions have a power tail with exponent of -2 or smaller. Possible exceptions are drugs like amiodarone with anomalous distribution kinetics (deep tissue trapping) which are characterized by a power-law tail and an apparent lack of equilibrium distribution, corresponding to a fractional-in-time derivative formulation of kinetics.

Compact sources in the Bologna Complete Sample: high-resolution VLA observations and optical data

Among radio galaxies, compact sources are a class of objects not yet well understood, and most of them cannot be included in classical populations of compact radio sources (flat spectrum AGN or compact steep spectrum sources). Our main goal is to analyze the radio and optical properties of a sample of compact sources and compare them with FRI/FRII extended radio galaxies. We selected in the Bologna Complete Sample a sub sample of Compact sources, naming it the C BCS sample. We collected new and literature sub-arcsecond resolution multi-frequency VLA images and optical data. We compared total and nuclear radio power with optical emission line measurements. The [OIII] luminosity - 408 MHz total power relation found in High and Low excitation galaxies, as well as in young (CSS) sources, holds also for the C BCSs. However, C BCSs present higher [OIII] luminosity than expected at a given total radio power, and they show the same correlation of Core Radio Galaxies, but with a higher radio power. C BCSs appear to be the high power tail of Core Radio Galaxies. For most of the C BCSs, the morphology seems to be strongly dependent to the presence of dense environments (e.g. cluster or HI-rich galaxies) and to a low age or restarted radio activity.

A multivariate normal law for Turing’s formulae

This paper establishes a sufficient condition for Turing’s formulae of various orders to have asymptotic multivariate normality. As an application, a consistent estimator of the tail under a discrete power tail model is also described.

Implicit renewal theorem for trees with general weights

Consider distributional fixed point equations of the form R=Df(Q,Ci,Ri,1≤i≤N), where f(⋅) is a possibly random real-valued function, N∈{0,1,2,3,…}∪{∞}, {Ci}i∈N are real-valued random weights and {Ri}i∈N are iid copies of R, independent of (Q,N,C1,C2,…); =D represents equality in distribution. Fixed point equations of this type are important for solving many applied probability problems, ranging from the average case analysis of algorithms to statistical physics. We develop an Implicit Renewal Theorem that enables the characterization of the power tail behavior of the solutions R to many equations of multiplicative nature that fall into this category. This result extends the prior work in Jelenković and Olvera-Cravioto (2012) [16], which assumed nonnegative weights {Ci}, to general real-valued weights. We illustrate the developed theorem by deriving the power tail asymptotics of the solution R to the linear equation R=D∑i=1NCiRi+Q.

Expansions for the Distribution of the Maximum from Distributions with a Power Tail when a Trend is Present

We give expansions about the second type of extreme value (EV2 or Frechet) distribution in inverse powers of the sample size, n + 1, for the sample maximum Mn when the jth observation is μ(j/n) + ej, μ(·) is any smooth trend function and the residuals e0, ..., en are independent with a common Pareto type distribution. We show that the distribution of the maximum has a triple expansion in inverse powers of n. We give the likelihood for this case and illustrate its practical value using simulated and real data sets.