Statistical Spread Research Articles

Analysis of the TRAPU irradiation in PHENIX with TRIPOLI-4® and DARWIN-3 for the validation of fast reactor fuel depletion calculations

The knowledge of the final inventory in the core of a Fast Reactor is required for many purposes, such as safety issues, reprocessing concerns or conception of new reactors. DARWIN-3 is the CEA code that aims to be the new reference for deterministic fuel depletion calculations. Composed of the deterministic neutronic code APOLLO3® and the depletion module MENDEL, it therefore needs to be validated by comparisons to experimental results or other fuel depletion codes.In this paper, the DARWIN-3 package performances are challenged for the validation of final inventory calculations in the core of a sodium-cooled fast reactor (SFR). This is done by reinterpreting the TRAPU experiment, which is a pin irradiation experiment that took place in the center of the PHENIX reactor between 1977 and 1979. During the TRAPU experiment, ten well-characterized fuel pins – of three different enrichment and Pu isotopic vectors – were placed in a subassembly near the center of the PHENIX core.At the end of the irradiation, the final amount of some isotopes results mainly from their initial concentration (e.g. plutonium, 241Am), whereas others – such as curium or 237Np – are produced exclusively during the irradiation; the final amount of these will be much more sensitive to potential modeling or calculation biases.We have computed Calculation/Experiment (C/E) ratios for different isotopic ratios at the end of the irradiation. A flux adjustment was performed in the calculations, in order to match the calculated 148Nd production to the experiment and avoid propagating a bias in the neutron flux calculation. The uncertainties take into account the experimental uncertainty, the statistical dispersion of the TRIPOLI-4® results and the statistical spread of the different sample results. For each calculated isotopic ratio, we have also assessed the associated uncertainty induced by the uncertainties on the nuclear data involved in the calculation.Comparisons with the previous deterministic package, DARWIN-2, composed of the ERANOS2 neutronic code and the PEPIN2 depletion module, as well as with the TRIPOLI-4® stochastic reference code, are performed.It appears that the production of uranium and plutonium are in agreement between DARWIN-3 and TRIPOLI-4®; the discrepancies observed for some americium and curium isotopes are explained by the slightly softer neutron energy spectrum in DARWIN-3 compared to TRIPOLI-4®.The disparities observed between DARWIN-2 and DARWIN-3 are also attributed to a difference in the neutron energy distribution calculated by the associated neutronic codes. This affects the calculation of the production of americium and curium, which are produced by reactions with large cross section resonances at low energy, where a small difference in the energy spectrum can result in a large difference on the reaction rate. The C/E for the production of those isotopes is worse with DARWIN-3 than it was with DARWIN-2; nevertheless, the production of neptunium, uranium and plutonium is compatible with both calculation codes.Due to its flexibility and attractive calculation time, DARWIN-3 allowed us to test some modeling hypothesis concerning the concentrations to be depleted, the type of decay chain, the effect of the nuclear data library and fuel temperature.

Novel low leakage and energy efficient dual-pullup/dual-pulldown repeater

Transistor threshold voltage (Vt) scaling causes higher power consumption by increasing the subthreshold leakage and short-circuit currents in CMOS circuits. Leakage currents are significant contributors to the overall power consumption of digital systems-on-chip as threshold voltage, channel length, and gate oxide thickness are reduced with CMOS technology scaling. A new dual-pullup/dual-pulldown (DPU/DPD) repeater is proposed in this paper for higher energy efficiency in low-voltage and low-frequency applications. The standby mode leakage power consumption is reduced by 59.11% with the proposed clock tree as compared to the conventional 3 level H-tree operating with a power supply voltage of 1.0V in a 45 nm CMOS technology. The short-circuit currents are suppressed by selectively employing high-Vt transistors in the repeaters. The clock network with the proposed buffer lowers the active mode energy consumption by up to 24.91% as compared to a conventional clock tree under equal silicon area constraint. Post layout results reveal that the statistical spread of clock skew in the DPU/DPD H-tree is also 20.60% lower than the conventional H-tree network.

Statistical spread on the displacement damage degradation of irradiated semiconductors

Non Ionizing Energy Loss (NIEL) is the metric conventionally used to scale displacement damage degradation of irradiated semiconductor materials. Degradation of many electrical parameters is scaled according to this average parameter. But some deviations from NIEL scaling approach are observed from time to time. The stochastic nature of irradiation is often ignored. But, the degradation is not necessarily proportional to the average degradation level given by NIEL. The scatter of the irradiation degradation level is studied in this paper. This analysis provides some hints in order to interpret some discrepancies observed between measurements and predictions made with NIEL. Reliability of NIEL scaling method, applied to dark current degradation, is discussed for Silicon and Gallium Arsenide optoelectronic devices.

Digital Multiphase PWM Integrated Module Generated from a Single Synchronization Source

This article introduces a new architecture for a high-resolution digital pulsewidth modulator (HR-DPWM), which generates multiple output phases, all synchronized and derived out of a single reference source. Constructed through digital standard-cell delay chain and simple combinatorial logic, the module produces PWM signals with configurable on-time, period and time-delay (between phases) with resolution of a single delay element. To minimize the statistical error spread (e.g., jitter error) between phases, a single delay-line is utilized to generate a master time-base while combinatorial logic assigns per-phase independent duty-ratio settings. The resultant module minimizes the time-diversity error between phases, as any uncertainty in the on-time generation is identical between phases. The solution is compact, flexible and scales with the number of phases. Since the entire architecture is realized through standard cells, the solution also scales with fabrication technology and is described by HDL, which translates onto hardware using automated process. The HR-DPWM module has been designed and fabricated on a 0.18 μm 5 V CMOS process, totaling 0.08 mm2 of effective silicon area. Experimental results of a four phase 13-bit HR-DPWM are provided, demonstrating high accuracy and linearity characteristics with time resolution of 200 ps and excellent matching and tracking between all phases.

Партисипативное принятие городских решений: правовые ожидания граждан

The article describes the results of sociological research aimed at identification of the citizens` demand in the legal consolidation of opportunities for and results of their participation in urban decision making. A mass semi-structured interview with a selection scope ensuring the statistical spread of no more than 5 % at the confidence level of 0,95 was used as a data collection method. The research was carried out in Tomsk in August 2020. The main results showed that the majority of residents asserted the right of participation in urban decision making and were ready to exercise it. The social participation experience allowed the citizens to identify the issues related to the execution of the decisions and communications during the decision elaboration and to formulate the areas of the participative interaction improvement. The improvement of procedures implies larger information sharing, reporting from municipal government and implementing regular surveys of citizens. From the citizens` standpoint, statutory consolidation is needed in respect of the obligations of the government authorities to make decisions together with citizens and in respect of the issues relevant for citizens, to react and execute decisions without delay, notably with specific punishment measures for non-performance or distortion of data. Obligatory procedures of participative technologies should be surveys, meetings, publication of all information, operation of a single phone number and a hot line, text message mailout, public control over performed works. The municipal practice in general is lagging behind the requests of the modern active, competent and demanding society.

Deformation-force effects of shape memory of TiNi alloys under conditions of incomplete martensitic transformation

The article is devoted to studying the influence of preliminary and plastic processing, applied stress, degree of phase transformation on the deformation effects manifested in conditions of incomplete martensitic transformation. The laws of generation and relaxation of reactive stresses were studied depending on the stiffness of the reaction, the magnitude of the preliminary deformation and the selected interval of heat changes. It is shown that the accumulation and return of deformation, the effect of generation and relaxation of reactive stresses in a narrow temperature range occurs only in structurally inhomogeneous objects, determined with the statistical spread of characteristic temperatures.

Tl concentration and its variation in a CsI(Tl) crystal for the CALIFA detector

One of the factors that can contribute to the resolution of long, doped inorganic scintillators used for nuclear spectroscopy is the variation of the dopant concentration over the length the detector crystal. In this work an investigation of such potential variations in one of the CsI(Tl) scintillators used in the calorimeter, CALIFA, of the R3B experiment at FAIR, has been performed using particle induced X-ray emission. No statistically significant gradient in doping level was found along the long axis of the investigated sample crystal and the mean value of the Tl concentration was measured to be 0.0839(38)% by weight. This corresponds to a light output of 97.3−1.7+1.3% relative to the maximum attainable light output according to previously published work. By taking the ±1σ bounds, the 3% statistical spread in the relative light output provides a good reference value of the minimum light-output non-uniformity observed for the CALIFA crystals. If the relative light output is estimated pointwise from a set of Tl concentration measurements a light-output non-uniformity of 4.6(2.4)% results. For a γ-ray energy of 662 keV the deduced variation in Tl concentration contributes with 0.48(6)% to the typical resolution of 7.74(6)% measured with a collimated source along the crystal main axis. The result is of interest for the characterization of the detector system performance and for realistic simulations of the light collection process in detector systems that are used for nuclear spectroscopy and calorimetry.

An Analytical Approach to Estimate the Effect of Surface Roughness on Particle Rebound

Atmospheric air is always contaminated by liquid or solid particles of different size, concentration and chemical composition. This leads to performance degradation during the operation of stationary or flying gas turbines. Erosion and the deposition of particles along the flow path are of particular importance. Multiple numerical studies investigated the influences of these phenomena. However, the basic challenge of modelling the particle wall interaction and its data spread with sufficient accuracy remains. In this work a model that estimates the statistical spread of rebound data due to target surface roughness through analytical considerations is presented. The model predicts the local impact angle of an individual particle by evaluating how deep a particle can theoretically penetrate the target surface with respect to its size. Based on roughness profiles which have been found to be characteristic for performance deterioration in compressor application a sensitivity study is conducted. A dimensionless roughness parameter Φ_R was found that characterizes the effect of target surface roughness on rebound spread data. The spread model is connected with a quasi-physical model, to evaluate the effect of surface roughness for a particle’s individual rebound behaviour. The synthesized data is discussed by taking into account measurement data reported in literature.

Synchrotron X-Ray Microdiffraction Investigation of Scaling Effects on Reliability for Through-Silicon Vias for 3-D Integration

Synchrotron x-ray microdiffraction has been applied to TSV characterization in various studies for nondestructive inspection with submicron resolution due to its high beam intensity and penetration depth. In this paper, the application of this technique to TSV investigations is examined and the correlation of the plastic deformation to the microstructure and extrusion behavior along with the effect of TSV dimensional scaling is examined. It is shown that the variability of the copper microstructure and resulting TSV behavior requires a larger number of samples in order to report statistically significant observations. The role of the microstructure in creating statistical scatter is demonstrated through microdiffraction measurements of grain orientation correlated with the observed peak widening, which shows that degraded TSV reliability is largely due to the high elastic anisotropy of copper. After taking the statistical variations into account, the scaling effect was clearly observed, with larger plastic deformation in $2~\mu \text{m}$ diameter TSVs than in $5~\mu \text{m}$ diameter TSVs consistent with microstructure variations. This is confirmed by TSV extrusion measurements, which show that the magnitude and statistical spread of the via extrusion for the $2~\mu \text{m}$ diameter TSVs is higher than that of the $5~\mu \text{m}$ diameter TSVs. These results, validated by thermomechanical simulation, demonstrate first that large sample sizes are required in copper TSV investigations due to high variability, which is not improved with scaling.

Using a statistical model of past wildfire spread to quantify and map the likelihood of fire reaching assets and prioritise fuel treatments

We present a method to quantify and map the probability of fires reaching the vicinity of assets in a wildfire-prone region, by extending a statistical fire spread model developed on historical fire patterns in the Sydney region, Australia. It calculates the mean probability of fire spreading along sample lines around assets, weights the probability according to ignition probability and also estimates the change in spread probability that fuel reduction in treatment blocks would achieve. We have developed an R package WildfireRisk to implement the analysis and demonstrate it with two case studies in forested eastern Australia. The probability of a fire reaching the vicinity of an asset was highest in the heavily forested parts of each case study, but when weighted for ignition probability, the high probability shifted to the wildland–urban interface. Further, when weighted by asset location, high-priority areas for treatment were in blocks next to the wildland–urban interface. This method is objective, fast and based on the behaviour of real historical fires. We recommend its use in wildfire risk planning, as an adjunct to heuristic methods and simulations. Additional functionality can be incorporated into our method, for instance via a function for building impact.

The effective control of Cu through-silicon via extrusion for three-dimensional integrated circuits by a metallic cap layer

This work demonstrated a new and promising approach to control via extrusion for three-dimensional integrated circuits (3DICs). By depositing 50 nm of Ta as a metallic cap, a significant reduction in both the magnitude and the statistical spread of extrusion was achieved. Thermo-mechanical and interfacial characterization were further carried out to study the mechanism of the observed effect. The results suggested that the Ta cap layer was able to effectively suppress the mass transport at via top surface and along grain boundaries, therefore reducing extrusion.

Comparative effect of land plyometric and aquatic plyometric training on lower limb explosive strength of athletes

Objective: The objective of the present study was to find out the Effect of Land Plyometric and Aquatic-based Plyometric Training on Lower Limb Explosive Strength of district level Athletes. Subject: Thirty six (N = 36) district level athletes were randomly selected as subjects for the present study from Nadia district of West Bengal. The age ranged from 12-18 years. Group division: All the subjects were divided into three equal groups: i) Land Plyometric training Group (N =12) as experimental group–I ii) Aquatic Plyometric Training Group (N=12) as experimental group–II and iii) Control Group (N=12). Equated group design was adopted in the present study. Experimental Protocol: Plyometric training was intervened for fourteen weeks on both the experimental groups. Experimental group-I underwent land Plyometric training whereas experimental group-II underwent aqua-based Plyometric training for fourteen weeks continuously for three days in a week and 90 min per day as per the structured training schedule. But the control group did not involve in the treatment program. During the training period participants of every group were allowed to do their routine activities as it was not under the control of the researchers. Variable Studied: In the present study explosive leg strength was measured through jumping ability along vertical as well as horizontal direction which was measured by Sargent jump and standing board jump respectively. Statistical analysis: To find out significant difference in lower limb explosive strength among the groups in pre and post intervention condition; analysis of covariance (ANCOVA) was conducted. To find out the exact location of the difference within different groups Tukey’s LSD test was adapted as post hoc test. The significance of means were tested at p<0.05 level. For statistical calculations Excel Spread Sheet of windows version 7 was used. Results: It was observed that the F value was significant at 0.05 level. Tukey’s post hoc test confirmed that both Land Plyometric and Aquatic Plyometric training groups improved significantly with respect to the control group in Leg Explosive Strength. But no significant difference was observed between land Plyometric training group (experimental group-I) and aquatic Plyometric training group (experimental group-II) which confirmed that both type of training was equally effective for developing explosive leg strength.

Characterization and Modeling of Temperature Effects in 3-D NAND Flash Arrays—Part I: Polysilicon-Induced Variability

This paper presents characterization and modeling results exploring the temperature dependence of the electrical characteristics of 3-D NAND Flash strings. Experimental data over a wide temperature range are used to calibrate a Technology Computer-Aided Design model for current transport through the polysilicon channel of the strings, which is then used to investigate the role of grain boundaries on string conduction. Results reveal that the variability in the grain configuration in the strings introduces a nonnegligible statistical spread in the temperature dependence of the threshold voltage ( ${V}_{T}$ ) of the memory cells, which acts as a broadening contribution to the array ${V}_{T}$ distribution when temperature is changed. The experimental and modeling activities will be extended in Part II of this paper to explore the temperature dependence of the ${V}_{T}$ instability caused by random telegraph noise.

A Hydraulic MultiModel Ensemble Framework for Visualizing Flood Inundation Uncertainty

AbstractWhile deterministic forecasts provide a single realization of potential inundation, the inherent uncertainty associated with forecasts also needs to be conveyed for improved decision support. The objective of this study was to develop an ensemble framework for the quantification and visualization of uncertainty associated with flood inundation forecast maps. An 11‐member ensemble streamflow forecast at lead times from 0 to 48 hr was used to force two hydraulic models to produce a multimodel ensemble. The hydraulic models used are (1) the International River Interface Cooperative along with Flow and Sediment Transport with Morphological Evolution of Channels solver and (2) the two‐dimensional Hydrologic Engineering Center‐River Analysis System. Uncertainty was quantified and augmented onto flood inundation maps by calculating statistical spread among the ensemble members. For visualization, a series of probability flood maps conveying the uncertainty in forecasted water extent, water depth, and flow velocity was disseminated through a web‐based decision support tool. The results from this study offer a framework for quantifying and visualizing model uncertainty in forecasted flood inundation maps.

Outliers-out stack: a new algorithm for processing seismic data

Common midpoint (CMP) stacking is one of the essential stages in seismic data processing. Conventional straight mean stacking is based on the assumption that all signals are coherent while all noises are random, which is not always valid in practice. Consequently, many alternative stacking techniques have been introduced in the field of seismic data processing during the past five decades. In this study, a new alternative stacking procedure, called outliers-out (OlO) stack, is proposed and tested using both synthetic and field seismic data. The OlO stacking method is based on analysing the statistical spread of each time sample and excluding a distinctive range of outliers from each time sample. Outliers are calculated independently for each time sample based on the amplitudes distribution within the sample. The outliers’ exclusion process is automatic but it is also adjustable by the user to suite the data under processing. The experimental results of applying the proposed stacking method to both synthetic and field seismic data clearly show that the OlO stacking technique outperforms conventional stacking techniques in terms of the temporal resolution and lateral coherency of the output seismic reflections. Results also show that the tuning function in the OlO stacking algorithm is efficient in dealing with different types of seismic data.

Development of a time-of-flight measurement technique in plasma induced by a СO2 laser

Experiments on the irradiation of a carbon target with СО2-laser pulses in the free-running mode at a radiation-flux density of 1.3 × 1011 W/cm2 and the time-of-flight technique for measuring the characteristics of the plasma ion component are described. The characteristics of the ion component of plasma that expands along the normal to the target and the statistical spread of the mean values were obtained. As a result of the measurements, the energy spectra of the plasma expansion and the partial ion currents at a chosen distance of the plasma drift from the target were reconstructed. The high time resolution of this technique made it possible to reconstruct the escape times of individual groups of ions from a heated region on the scale of the duration of the heating laser pulse.

Cognitive Development of School-Age Hypoplastic Left Heart Syndrome Survivors: A Single Center Study.

Neurological and radiologic research results show an abnormal cerebral microstructure as well as abnormal neurodevelopment in patients treated for hypoplastic left heart syndrome. The aim of this study was to assess the varying cognitive performance these children have developed in dependence upon prenatal diagnosis, surgical techniques, surgical learning effects, anatomy, perfusion techniques, gender, pedagogic, and sociodemographic parameters in comparison to age-adjusted normative values. School-age children (6.3-16.9years) with hypoplastic left heart syndrome, who were treated at the Children's heart Center Linz between 1997 and 2009, (n=74), were surveyed in reference to cognitive achievements. 43 patients were examined prospectively by psychologists using the Wechsler intelligence scale for children IV in order to determine the respective total intelligence quotient index for each child's developmental stage. The mean index was 84.5 (percentile rank 26.4). The statistical spread and standard deviation ranged from a minimum of 40 to a maximum of 134±20.8. The results for verbal comprehension, perceptual reasoning, and processing speed corresponded with total index results and were thus lower than the mean value of the normative values. The assessment of working memory showed results in the average. Prenatal diagnosis, type of lung perfusion, anatomy, and various cerebral perfusion techniques did not significantly affect the cognitive results of the patients. The results show that hypoplastic left heart syndrome patients can be successfully tutored formally as well as personally in cognitive areas, although when compared to healthy children, they showed lower results for intellectual area parameters.

Defining the Influence of Horizontal Grid Spacing on Ensemble Uncertainty within a Regional Modeling Framework

Abstract Numerical weather prediction (NWP) models are limited with respect to initial and boundary condition data and possess an incomplete description of underlying physical processes. To account for this, modelers have adopted the method of ensemble prediction to quantify the uncertainty within a model framework; however, the generation of ensemble members requires considerably more computational time and/or resources than a single deterministic simulation, especially at convection-allowing horizontal grid spacings. One approach to solving this issue is the development of both a large and small horizontal grid spacing model framework over the same domain for ensemble and deterministic simulations, respectively. This approach assumes that model grid spacing has no influence on model uncertainty; therefore, the objective of this paper is to quantify the influence of horizontal grid spacing on the statistical spread of NWP model ensembles over a regional domain. A series of 24-h simulations using the Weather Research and Forecast (WRF) Model are generated over a static domain with horizontal grid spacings of 35, 25, 15, and 9 km, using both a stochastic kinetic energy backscatter scheme and a multiphysics ensemble approach. Results indicate that horizontal grid spacing does influence the magnitude of uncertainty within an ensemble, although the exact magnitude and type of statistical relationship (direct versus inverse) varies by case. As such, at shorter lead times (<12 h) the dominant atmospheric process associated with each event and the type of ensemble being used outweigh the individual impacts of horizontal grid spacing on ensemble spread.

Stochasticity and predictability in terrestrial planet formation

Terrestrial planets are thought to be the result of a vast number of gravitational interactions and collisions between smaller bodies. We use numerical simulations to show that practically identical initial conditions result in a wide array of final planetary configurations. This is a result of the chaotic evolution of trajectories which are highly sensitive to minuscule displacements. We determine that differences between systems evolved from virtually identical initial conditions can be larger than the differences between systems evolved from very different initial conditions. This implies that individual simulations lack predictive power. For example, there is not a reproducible mapping between the initial and final surface density profiles. However, some key global properties can still be extracted if the statistical spread across many simulations is considered. Based on these spreads, we explore the collisional growth and orbital properties of terrestrial planets which assemble from different initial conditions (we vary the initial planetesimal distribution, planetesimal masses, and giant planet orbits). Confirming past work, we find that the resulting planetary systems are sculpted by sweeping secular resonances. Configurations with giant planets on eccentric orbits produce fewer and more massive terrestrial planets on tighter orbits than those with giants on circular orbits. This is further enhanced if the initial mass distribution is biased to the inner regions. In all cases, the outer edge of the system is set by the final location of the $\nu_6$ resonance and we find that the mass distribution peaks at the $\nu_5$ resonance. Using existing observations, we find that extrasolar systems follow similar trends. Although differences between our numerical modelling and exoplanetary systems remain, we suggest that CoRoT-7, HD 20003, and HD 20781 may host undetected giant planets.

Low-energy negative muon interaction with matter

Using simulated data, obtained with the FLUKA code, we derive empirical regularities about the propagation and stopping of low-energy negative muons in hydrogen and selected solid materials. The results are intended to help the preliminary stages of the set-up design for experimental studies of muon capture and muonic atom spectroscopy. Provided are approximate expressions for the parameters of the the momentum, spatial and angular distribution of the propagating muons. In comparison with the available data on the stopping power and range of muons (with which they agree in the considered energy range) these results have the advantage to also describe the statistical spread of the muon characteristics of interest.