Experimental Estimates Research Articles

Assessing the elicitation of perceived status quo information as a tool to increase survey engagement and enhance accuracy of preference estimates in discrete choice experiments

Assessing the elicitation of perceived status quo information as a tool to increase survey engagement and enhance accuracy of preference estimates in discrete choice experiments

Temporal forecasting by converting stochastic behaviour into a stable pattern in electric grid

The malfunction variables of power stations are related to the areas of weather, physical structure, control, and load behavior. To predict temporal power failure is difficult due to their unpredictable characteristics. As high accuracy is normally required, the estimation of failures of short-term temporal prediction is highly difficult. This study presents a method for converting stochastic behavior into a stable pattern, which can subsequently be used in a short-term estimator. For this conversion, K-means clustering is employed, followed by long-short-term memory and gated recurrent unit algorithms are used to perform the short-term estimation. The environment, the operation, and the generated signal factors are all simulated using mathematical models. Weather parameters and load samples have been collected as part of a dataset. Monte-Carlo simulation using MATLAB programming has been used to conduct experimental estimation of failures. The estimated failures of the experiment are then compared with the actual system temporal failures and found to be in good match. Therefore, to address the gap in knowledge for any future power grid estimated failures, the achieved results in this paper form good basis for a testbed to estimate any grid future failures.

A time‐efficient computational binding affinity estimation protocol with utilization of limited experimental data: A case study for adenosine receptor

AbstractEstimating binding affinity is a crucial step in the drug discovery process. In computer‐aided drug design, this challenge can be divided into two main tasks: finding the correct binding pose and estimating the binding free energy. In this study, we propose a new binding affinity estimation protocol that utilizes molecular docking with limited experimental data and estimates binding affinity using molecular dynamics simulation. A custom scoring function was employed during docking to identify an improved initial binding pose, and the linear interaction energy method with an optimized coefficient was used for binding affinity estimation. The protocol was validated with an external data set and applied to modafinil and its derivatives to rank their binding affinities to adenosine A2A receptors (ADORA2A) as a case study. This approach could be both time‐efficient and valuable for computational drug discovery, particularly when experimental data is limited.

Beam attenuation coefficient for different water turbidities

Interest in underwater optical communications has grown in recent years. A key aspect for the development of such systems is the modeling of light signal propagation in turbid water. In this paper, we present an experimental estimation of the light beam attenuation coefficient by varying the turbid water conditions with pollutants and also considering sea and lake water. The estimation of the beam attenuation coefficient c is based on laboratory measurements of the optical signal-to-noise ratio (SNR) for underwater transmissions and an analytical model of c as a function of SNR. To assess the reliability of the estimation procedure, c has been estimated in the case of clear water and the value obtained is very close to that reported in many studies. Next, c has been estimated for different water conditions. In particular, the results show that the value of c for polluted waters varies between 2.875m−1 and 15.675m−1. In addition, the values of c for lake and clear sea water are 0.6m−1 and 0.9m−1, respectively.

Real-space renormalisation approach to the Chalker–Coddington model revisited: Improved statistics

The real-space renormalisation group method can be applied to the Chalker–Coddington model of the quantum Hall transition to provide a convenient numerical estimation of the localisation critical exponent, ν. Previous such studies found ν∼2.39 which falls considerably short of the current best estimates by transfer matrix (ν=2.593+0.005−0.006) and exact-diagonalisation studies (ν=2.58(3)). By increasing the amount of data 500 fold we can now measure closer to the critical point and find an improved estimate ν=2.51+0.11−0.11. This deviates only ∼3% from the previous two values and is already better than the ∼7% accuracy of the classical small-cell renormalisation approach from which our method is adapted. We also study a previously proposed mixing of the Chalker–Coddington model with a classical scattering model which is meant to provide a route to understanding why experimental estimates give a lower ν∼2.3. Upon implementing this mixing into our RG unit, we find only further increases to the value of ν.

On-Board Diagnostics for Li-Ion Batteries Using Electrochemical Impedance Spectroscopy (EIS)-Based Health Estimation Models

There exists a growing need for standardized On-Board Diagnostics (OBD) for electric vehicles [1] to provide accurate health metrics and guarantees to both consumers and manufacturers.Previous work has shown the powerful LIB capacity-based State-of-Health (SoH) estimation capability of Electrochemical Impedance Spectroscopy (EIS) measurements and data-driven models [2] [3]. Since EIS measurements are dependent not only on SoH but also State-of-Charge (SoC) and temperature [4], it is important that the measurements are conducted after the cell reaches an equilibrium, and that these other variables are also tracked. Although EIS measurements are somewhat quicker than some traditional capacity-determination experimental methods, the time taken for such measurements is not insignificant. Therefore, building a pipeline to determin the EIS frequency measurements most important for SoH estimation is an important task in developing a suitable EIS-based OBD. By exploring a frequency range between 0.1 and 200 Hz, we study EIS measurements related to diffusion and charge transfer processes in LIB operation [5], with each process being partially distinguishable due to their varying timescales.In this work, using EIS data collected from 5Ah LIBs with an NMC-111 cathode and a graphite anode at various SoCs (0, 25, 50, 75 and 100%) and cell lifetime (0, 10, 20, 40 and 90 days) as input features, we develop sequential, data-driven health estimation models for LIBs. The 22 cells used for this analysis have been aged over a period of 90 days in two different ways: either through active cycling at different C-rates (0.2 and 1C) and temperatures (0, 25 and 40⁰C), or passive “calendar aging” where the cells are left without use at a specific temperature and SOC. Using feature attribution techniques (Shapley values, feature occlusion, etc.), we find the most influential of the frequency ranges in the EIS measurements that relate strongly with cell performance degradation. To develop a streamlined and efficient SoH estimation framework, we formulate an optimization problem to find the EIS experimental design in terms of frequency ranges that delivers maximum accuracy in SoH estimation at different points in the lifetime of the cell. These streamlined and optimized EIS experimental designs and SoH estimation models can be used directly in the development of rapid and efficient on-board diagnostic tools.

Unlocking superior performance of broadband powerful mid-IR optical parametric amplifiers with a BaGa2GeS6 crystal pumped at 1.24 µm.

We report on the development of a tunable (1.5-6.5 µm) femtosecond optical parametric amplifier (OPA) based on a novel, to the best of our knowledge, BaGa2GeS6 (BGGS) crystal with a Cr:Forsterite pumping laser. Total conversion efficiency as high as 28% is achieved in a robust two-stage setup resulting in the generation of a 340-µJ 1.67-µm signal and 100-µJ 4.65-µm idler pulses. A 5-optical-cycles 94-fs 6-µm idler pulses are demonstrated with a propriate dispersion compensation by Ge and GaAs plates. An experimental estimate is given for the effective nonlinearity of a BGGS material, which for our nonlinear process reaches 19.5 pm/V for Type II phase matching. The crystal is additionally tested as a final amplifier in a high-energy OPA, where total output reaches 1.2 mJ with more than 40% conversion efficiency. The demonstrated high nonlinearity, high damage threshold, and chemical stability of the polished surface make BGGS crystal an ideal candidate for the development of high-energy OPAs with multi-millijoule pumping lasers.

Examination of static fission properties of 236\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{236}$$\\end{document}U and 233\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{233}$$\\end{document}Th using Cassinian oval parametrization within the macroscopic–microscopic approach

We have conducted a thorough analysis of the potential energy surfaces (PES) in 236\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{236}$$\\end{document}U and 233\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{233}$$\\end{document}Th using the Cassini-ovals parameterization within the macro–micro approach. We employed the state-of-the-art immersion water flow (IWF) method to study the saddles on four-dimensional energy grids encompassing reflection-asymmetric shapes. For 233\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{233}$$\\end{document}Th, we computed the adiabatic potential energy surfaces by minimizing configurations with one blocked neutron within ten levels below and above the Fermi level. Our results show satisfactory agreement with empirical and experimental estimates for both nuclei, specifically regarding the first and second fission barriers. This suggests that our method holds promise in efficiently describing non-compact shapes while reducing the dimensionality of the space without sacrificing accuracy. Interestingly, employing Cassinian oval parameterization fails to reveal a pronounced, hyper-deformed third minimum in the potential energy landscape. Instead, only a shallow third minimum is observed for 233\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{233}$$\\end{document}Th, while in 236\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{236}$$\\end{document}U, this minimum ultimately vanishes. This finding holds significant importance when considering the modeling of fission cross-sections.

Closing the gaps in experimental and observational crop response estimates: a bayesian approach

Abstract A stylized fact of African agriculture is that crop responses to inorganic fertilizer application derived from experimental studies are often substantially greater than those from observational studies (e.g. surveys and administrative data). Recent debates on relative costs and benefits of expensive farm input subsidy programs in Africa, have raised the importance of reconciling these estimates. Beyond mean response differences, this paper argues for including parameter uncertainty and heterogeneity arising from variations in soil types, environmental conditions, and management practices. We use a Bayesian approach that combines information from experimental and observational data to model uncertainty and heterogeneity in crop yield responses. Using nationally representative experimental, survey, and administrative datasets from Malawi, we find that: (1) crop responses are low in observational data, (2) there are large spatial heterogeneities, and (3) based on sensitivity analysis, ignoring parameter uncertainty and spatial heterogeneity in crop responses can lead to questionable policy prescriptions.

Improved Amott Method to Determine Oil Recovery Dynamics from Water-Wet Limestone Using GEV Statistics

Counter-current spontaneous imbibition of water is a critical oil recovery mechanism. In the laboratory, the Amott test is a commonly used method to assess the efficacy of brine imbibition into oil-saturated core plugs. The classic Amott-cell experiment estimates ultimate oil recovery, but not the recovery dynamics that hold fundamental information about the imbibition mechanisms. Retention of oil droplets at the outer core surface and initial production delay are the two key artifacts of the classic Amott experiment. This retention, referred to here as the “external-surface oil holdup effect” or simply “oil holdup effect”, often results in stepwise recovery curves that obscure the true dynamics of spontaneous imbibition. To address these holdup drawbacks of the classic Amott method, we modified the Amott cell and experimental procedure. For the first time, using water-wet Indiana limestone cores saturated with brine and mineral oil, we showed that our improvements of the Amott method enabled accurate and reproducible measurements of oil recovery dynamics. Also for the first time, we used the generalized extreme value (GEV) statistics to describe oil production histories from water-wet heterogeneous limestone cores with finite initial water saturations. We demonstrated that our four-parameter GEV model accurately described the recovery dynamics, and that optimal GEV parameter values systematically reflected the key characteristics of the oil–rock system, such as oil viscosity and rock permeability. These findings gave us a more fundamental understanding of spontaneous, counter-current imbibition mechanisms and insights into what constitutes a predictive model of counter-current water imbibition into oil-saturated rocks with finite initial water saturation.

Experimental and numerical estimation of thermal conductivity of bio-based building composite materials with an enhanced thermal capacity

The paper tackles the important problem of estimating and predicting the thermal conductivity of bio-based building materials that can help decarbonize the building sector. Knowledge and the possibility to optimize their insulating properties is the first criterion for determining the ability of their use in the building sector. The novel yet not well-studied hemp shives and magnesium binder composites with improved thermal mass by microencapsulated phase change material (PCM) were considered. The samples of composites without PCM having different densities as well as with different amounts of microencapsulated PCM and the same density were manufactured and tested experimentally in different states, i.e., dry and after conditioning at relative humidity (RH) of 50, 75, and 90 %, and in the case of samples with PCM also at different average measurement temperatures selected with respect to the phase change range of the PCM. A novel method of predicting bio-based composites' effective thermal conductivity tensor was also developed. The method is based on the numerical solution of the heat conduction equation at the micro-scale considering real composite microstructure. The method was tuned using micro-computed tomography (μCT) data with the microstructure of composites without PCM and then applied to predict the thermal conductivities of composites with PCM, utilizing computational domains with an artificially distributed PCM in the binder. The experimental testing of composites without PCM revealed an apparent effect of increasing thermal conductivity with rising sample density and RH applied during conditioning. With an increase in density from 394 to 576 kg/m3, their thermal conductivities varied from 0.105 to 0.159 W/m/K for the dry state and from 0.157 to 0.241 W/m/K for RH 90 %. A similar effect of sample state and RH was observed for composites with microencapsulated PCM, which had the highest thermal conductivity, equal to 0.265 W/m/K, for the lowest PCM amount and RH 90 %. Moreover, a decrease in composites' effective thermal conductivity with an increase in PCM fraction was observed, except for the lowest PCM fraction, for which it increased. It also rose with increasing the average measurement temperature. The developed micro-scale-based numerical method allowed for predicting the thermal conductivities of composites with accuracies below 4.1 and 7.2 % for composites without and with PCM, respectively, except for the composite with the lowest amount of PCM, which behaved differently. Thus, its suitability for designing and optimizing bio-based composites was shown.

Comprehensive investigation of bond properties of CFRP cables with concrete and mortar

This study investigated the bond properties of carbon fiber reinforced polymer (CFRP) cables with concrete and mortar. Analyses focused on the bond-slip behavior considering various factors, such as CFRP cable types (e.g., CFRP rod and strand), surface treatments, fixed end materials (e.g., concrete and mortar). Remarkably, the material type and compressive strength at the fixed end were found to have no discernible impact on bond-slip behavior. Conversely, the type of CFRP cable and its surface treatment emerged as pivotal factors influencing bonding strength outcomes. Employing the modified Bertero-Popov-Eligehanusen (BPE) model, a comparative evaluation was performed between experimental results and theoretical estimation of bond-slip behavior. Furthermore, image processing analysis revealed a similar bonding strength of CFRP cables with both concrete and mortar. This similarity can be attributed to the sparser distribution of coarse aggregates around cables in concrete samples, implying that the cementitious phase primarily governed the bond properties, resulting in consistent bonding strengths across different fixed end materials. Overall, this study sheds light on the intricate interplay between CFRP cable types, surface treatments, and material compositions, ultimately contributing to a deeper understanding of bond properties and their implications for various structural applications.

Effect of partition walls on the vibration serviceability of cross-laminated timber floors

The current standards need more specific serviceability criteria for Cross-Laminated Timber (CLT) floors. This paper presents a comprehensive analysis of a relevant case study in Norway, which presented unexpectedly high accelerations in the CLT floors after construction. The lack of a sufficiently detailed design process resulted in the poor vibration performance of the floors, which partially compromised their functionality. The paper thoroughly investigates and discusses the experimental dynamic characterization of seven CLT floors within the considered building. The authors estimated the modal parameters and serviceability metrics based on both Eurocode 5 (EC5) and the new draft version of it. Specifically, the authors compared the analytical predictions of the fundamental frequency and the root mean square acceleration against the corresponding experimental estimations. Using a sensor-roving approach, a dense sensor configuration was adopted to describe seven floors’ mode shapes and serviceability metrics. These metrics include mean square acceleration and Vibration Dose Value. The scenarios examined in this study shed light on the significance of partition walls, a factor not considered in the practical design for serviceability verifications. The presence of partition walls can enhance the vibration comfort of timber floors by providing a stiffening effect, leading to a significant increase in the first fundamental frequency. A parametric finite element model was developed using OpenSeesPy to investigate this phenomenon further. The model, firstly validated against selected experimental results, is employed to assess the influence of partition walls on floor dynamics. The model predicts the increase in the first frequency caused by randomly generated partition walls. The paper proposes an empirical expression calibrated on the simulated data to estimate the relative increment of the floor’s fundamental frequency based on the partition walls’ layout. This formulation can be included in the analytical expression enclosed in the EC5 draft to predict the fundamental frequency of timber floors.

Nuclear Quantum Effects on the Electronic Structure of Water and Ice.

The electronic properties and optical response of ice and water are intricately shaped by their molecular structure, including the quantum mechanical nature of the hydrogen atoms. Despite numerous previous studies, a comprehensive understanding of the nuclear quantum effects (NQEs) on the electronic structure of water and ice at finite temperatures remains elusive. Here, we utilize molecular simulations that harness efficient machine-learning potentials and many-body perturbation theory to assess how NQEs impact the electronic bands of water and hexagonal ice. By comparing path-integral and classical simulations, we find that NQEs lead to a larger renormalization of the fundamental gap of ice, compared to that of water, ultimately yielding similar bandgaps in the two systems, consistent with experimental estimates. Our calculations suggest that the increased quantum mechanical delocalization of protons in ice, relative to water, is a key factor leading to the enhancement of NQEs on the electronic structure of ice.

Exploiting small punch test for mechanical characterization of cold sprayed deposits

Conventional testing procedures often encounter challenges to characterize the mechanical properties of deposits of limited thickness such as coatings. To overcome this limitation, the literature has explored various miniature-testing methods, and, among these, the small punch test has emerged as a promising solution offering the main advantage of requiring a minimal volume of material. This study focuses on cold sprayed deposits in as-sprayed and thermally treated conditions and presents the results of an experimental campaign of mechanical characterization of 316L steel and copper deposits. In parallel, small punch tests are simulated numerically with inverse analysis to estimate comprehensively the stress-strain curves. Results suggest an extremely brittle behavior of the as-sprayed specimens and a good agreement between the experimental and numerical estimations of the mechanical properties of the ductile thermally treated specimens. Ultimately, the findings highlighted the sensibility of the small punch test to the microstructure and its gradients of cold sprayed deposits.

Researches and measurements of high-sensitive seismometers at experimental base «Obninsk»

One of the main directions of new seismometers development for seismological monitoring systems is decreasing the instrumental noise level and nonlinearity distortions of the instrumental seismic channels. In accordance with modern requirements for high-sensitive seismological stations, the instrumental noise of seismometers should be at least three times less than local seismic background noise. By theoretical estimations modern high-sensitive seismometers have high level features: instrumental noise is lower than the minimal seismic background noise, nonlinearity factor is about 0,01% and less. However, the problem of experimental estimation of these parameters in conditions of ambient seismic backgrounds remains to be under consideration. This problem is especially important during development and production of new seismometers. The article presents some results of studying and measuring the instrumental noise level and nonlinearity factor in channels of broadband and short-period seismometers carried out at the experimental base “Obninsk”. To provide a high precision of measurements, the narrow-band digital filtration and spectrum-correlation data procession technique decreasing influence of the seismic background motion on the results uncertainty were used. Due to stable temperature and insulation in the gallery of 30-meter depth, a 20-30% uncertainty for instrumental noise characteristic measuring, which is 10-30 times lower than local seismic background noise, and 0.0004% uncertainty of nonlinearity factor measuring were achieved. The seismological and environmental conditions at the experimental base “Obninsk” of the Geophysical Survey of RAS provide necessary abilities for researche and measurement of instrumental noise characteristics and non-linear distortion factor of high-sensitive seismometers with satisfactory accuracy.

Nuclear elastic scattering of protons below 250 MeV in FLUKA v4-4.0 and its role in single-event-upset production in electronics

FLUKA is among the general-purpose codes for the Monte Carlo simulation of radiation transport that are routinely employed to estimate the production of single-event-upsets (SEUs) in commercial static random access memories (SRAMs) exposed to radiation. Earlier studies concerning the production of SEUs in commercial SRAMs under proton irradiation revealed very good agreement between experimental measurements and FLUKA estimates of the SEU production cross section for proton energies above 20-30 MeV. However, at lower proton energies, where the cross section for SEU production in such low-critical-charge components increases drastically, a FLUKA underestimation of up to two orders of magnitude was observed. Preliminary analyses indicated that this underestimation was in great measure due to the lack of nuclear elastic scattering of protons below 10 MeV in FLUKA up to version 4-3.4. To overcome this limitation, a new model for the nuclear elastic scattering of protons has been developed, combining partial-wave analyses and experimental angular distributions. This newly developed model has been included in FLUKA v4-4.0, and leads to an order-of-magnitude improvement in the agreement between FLUKA and experimental cross sections for the production of SEUs in SRAMs under proton irradiation in the 1–10 MeV energy domain.

Experimental estimation of the amount of residual slag remaining inside orbital insertion stage solid rocket motor

Experimental estimation of the amount of residual slag remaining inside orbital insertion stage solid rocket motor

Understanding the Differences of Danusertib's Residence Time in Aurora Kinases A/B: Dissociation Paths and Key Residues Identified using Conventional and Enhanced Molecular Dynamics Simulations.

The accurate experimental estimation of protein-ligand systems' residence time (τ) has become very relevant in drug design projects due to its importance in the last stages of refinement of the drug's pharmacodynamics and pharmacokinetics. It is now well-known that it is not sufficient to estimate the affinity of a protein-drug complex in the thermodynamic equilibrium process in in vitro experiments (closed systems), where the concentrations of the drug and protein remain constant. On the contrary, it is mandatory to consider the conformational dynamics of the system in terms of the binding and unbinding processes between protein and drugs in in vivo experiments (open systems), where their concentrations are in constant flux. This last model has been proven to dictate much of several drugs' pharmacological activities in vivo. At the atomistic level, molecular dynamics simulations can explain why some drugs are more effective than others or unveil the molecular aspects that make some drugs work better in one molecular target. Here, the protein kinases Aurora A/B, complexed with its inhibitor Danusertib, were studied using conventional and enhanced molecular dynamics (MD) simulations to estimate the dissociation paths and, therefore, the computational τ values and their comparison with experimental ones. Using classical molecular dynamics (cMD), three differential residues within the Aurora A/B active site, which seems to play an essential role in the observed experimental Danusertib's residence time against these kinases, were characterized. Then, using WT-MetaD, the relative Danusertib's residence times against Aurora A/B kinases were measured in a nanosecond time scale and were compared to those τ values observed experimentally. In addition, the potential dissociation paths of Danusertib in Aurora A and B were characterized, and differences that might be explained by the differential residues in the enzyme's active sites were found. In perspective, it is expected that this computational protocol can be applied to other protein-ligand complexes to understand, at the molecular level, the differences in residence times and amino acids that may contribute to it.

Quantum Speed Limit for States and Observables of Perturbed Open Systems.

Quantum speed limits provide upper bounds on the rate with which a quantum system can move away from its initial state. Here, we provide a different kind of speed limit, describing the divergence of a perturbed open system from its unperturbed trajectory. In the case of weak coupling, we show that the divergence speed is bounded by the quantum Fisher information under a perturbing Hamiltonian, up to an error which can be estimated from system and bath timescales. We give three applications of our speed limit. First, it enables experimental estimation of quantum Fisher information in the presence of decoherence that is not fully characterized. Second, it implies that large quantum work fluctuations are necessary for a thermal system to be driven quickly out of equilibrium under a quench. Moreover, it can be used to bound the response to perturbations of expectation values of observables in open systems.