Satellite validation strategy assessments based on the AROMAT campaigns

The Airborne ROmanian Measurements of Aerosols and Trace gases (AROMAT) campaigns took place in Romania in September 2014 and August 2015. They focused on two sites: the Bucharest urban area and large power plants in the Jiu Valley. The main objectives of the campaigns were to test recently developed airborne observation systems dedicated to air quality studies and to verify their applicability for the validation of space-borne atmospheric missions such as the TROPOspheric Monitoring Instrument (TROPOMI)/Sentinel-5 Precursor (S5P). We present the AROMAT campaigns from the perspective of findings related to the validation of tropospheric NO2, SO2, and H2CO. We also quantify the emissions of NOx and SO2 at both measurement sites. We show that tropospheric NO2 vertical column density (VCD) measurements using airborne mapping instruments are well suited for satellite validation in principle. The signal-to-noise ratio of the airborne NO2 measurements is an order of magnitude higher than its space-borne counterpart when the airborne measurements are averaged at the TROPOMI pixel scale. However, we show that the temporal variation of the NO2 VCDs during a flight might be a significant source of comparison error. Considering the random error of the TROPOMI tropospheric NO2 VCD (σ), the dynamic range of the NO2 VCDs field extends from detection limit up to 37 σ (2.6×1016 molec. cm−2) and 29 σ (2×1016 molec. cm−2) for Bucharest and the Jiu Valley, respectively. For both areas, we simulate validation exercises applied to the TROPOMI tropospheric NO2 product. These simulations indicate that a comparison error budget closely matching the TROPOMI optimal target accuracy of 25 % can be obtained by adding NO2 and aerosol profile information to the airborne mapping observations, which constrains the investigated accuracy to within 28 %. In addition to NO2, our study also addresses the measurements of SO2 emissions from power plants in the Jiu Valley and an urban hotspot of H2CO in the centre of Bucharest. For these two species, we conclude that the best validation strategy would consist of deploying ground-based measurement systems at well-identified locations.

Numerical Study on the Hydrodynamic Performance of the DARPA Suboff Submarine for Steady Translation

This study was built upon previous works conducted by the authors in a series of numerical studies on submarine hydrodynamics and is aimed at enhancing the accuracy of computational fluid dynamics (CFD) application processes, which estimate the hydrodynamic performance of underwater vehicles for steady translation conditions in the horizontal and vertical planes. In an earlier work, the computed straight-ahead resistance of a submarine agreed with those of experiments within a comparison error of 2%. However, a maximum comparison error of approximately 20% was obtained for sway force under a steady translation condition. The Defense Advanced Research Projects Agency (DARPA) Suboff submarine model was adopted as a benchmark, and the computational modeling was based on the Reynolds-averaged Navier–Stokes (RANS) turbulence model for steady simulations. The curvature correction approach was tested to improve the computation of circumferential flow around the cylindrical hull, in particular. The dominant maneuvering coefficients were calculated using the computed forces and moments as a function of the yaw and pitch angles along with simplified equations of motion by fitting a curve to the plots. The hydrodynamic forces and moments exerted on the stern plane were individually computed using a locally refined mesh around the tail section. It was confirmed that the curvature correction approach improved the computational accuracy for the steady translation conditions, and general trends were captured over the tested yaw and pitch angles. However, some data points had notable comparison errors. Some of the estimated maneuvering coefficients agreed well between the CFD simulation and the experiments, whereas others had considerable comparison errors. The individually computed forces and moments exerted on the stern plane that had attack angles were inconsistent with those obtained in experiments. Those comparison errors may have been amplified by the complexity of configuration and arisen from differences in the experiments, such as the presence of a free surface and supporting strut to mount the hull to a carriage, and, perhaps, the geometrical differences owing to machining accuracy. The investigation of flow field at the propeller plane revealed that the wake distributions inside the nozzle were significantly affected by the angled stern planes; the reduced velocity area was expanded and shifted. Furthermore, harmonic analysis of the wake fraction was conducted, and several primary nth harmonics were observed, which were associated with the struts and stern planes. This result suggests the risk of higher noise levels associated with the number of blades.

Using the Total Survey Error Paradigm to Improve Cross-National Research on Religion

Cross-national research is an absolute necessity if we are to understand contemporary human societies in general and the role of religion in particular. To be useful, comparative survey research needs to meet high scientific standards of reliability and validity and achieve functional equivalence across surveys. This chapter examines how well-designed and well-executed cross-national/cultural survey research can best minimize error and maximize equivalence. The chapter first introduces the concept of total survey error (TSE), including interactions among the error components, its application when multiple surveys are involved, and comparison error across cross-national surveys. Second, obtaining functional equivalence and similarity in cross-national surveys is discussed. Third, the challenges of doing cross-national surveys are considered, as well as how combining traditional approaches for maximizing functional equivalence with the utilization of TSE can minimize comparison error and maximize comparative reliability and validity. Fourth, attention is given to minimizing comparison error in question wordings in general. Special attention is given to dealing with differences in language, structure, and culture. Lastly, specific issues relating to studying religion cross-nationally are examined.

Interpretation of Validation Results Following ASME V&V20-2009

Suggestions are made for modification and extension of the methodology and interpretations of ASME V&V 20-2009, Standard for Verification and Validation in Computational Fluid Dynamics and Heat Transfer. A more conservative aggregation of numerical uncertainty into the total validation uncertainty is recommended. A precise provisional demarcation for accepting the validation comparison error as an estimate of model error is proposed. For the situation where the validation exercise results in large total validation uncertainty, a more easily evaluated estimated bound on model error is recommended. Explicit distinctions between quality of the model and quality of the validation exercise are discussed. Extending the domain of validation for applications is treated by interpolating/extrapolating model error and total validation uncertainty, and adding uncertainty from the new simulation at the application point. Model form uncertainty and epistemic uncertainties in general, while sometimes important in model applications, are argued to not be important issues in validation.

Implementation and Evaluation of an Intervention for Children in Afghanistan at Risk for Substance Use or Actively Using Psychoactive Substances

The present study examined the impact of a novel intervention for children at risk for substance use or actively using substances that was provided to 783 children between 4 and 18 years of age in Afghanistan. They received the Child Intervention for Living Drug-free (CHILD) protocol while in outpatient or residential treatment. CHILD included age-appropriate literacy and numeracy, drug education, basic living safety, and communication and trauma coping skills. A battery of measures examined multiple child health domains at treatment’s start and end and 12 weeks later. For younger children, there were no significant Gender or Gender X Time effects (all p’s > .16 and .35, resp.). The time main effect was significant for all outcomes (all p’s < .00192, the prespecified per-comparison error rate). Post hoc testing showed significant improvements from residential treatment entry to completion for all scales. For older children, a time main effect was significant for (all p’s < .00192, the prespecified per-comparison error rate) all but one outcome. Community follow-up means were significantly lower than residential treatment entry means. CHILD had a positive impact on children, and treatment impact endured from posttreatment to follow-up assessment.

The Chrome Thin Coating Characteristics Using Ultrasonic Testing

According to the different thickness of the thin coatings, the echo signal of ultrasonic testing was extracted. The sound velocity in the coating medium was obtained by solving the mathematical model for transfer function and the time delay spectrometry method, and the coating thickness was calculated, the comparison error of the calculated thickness and the actual thickness, combined with the actual thickness of the coating. The results showed that, two kinds of testing methods are able to detect thin coating thickness.

Computational Fluid Dynamics Simulation of a Mesoscale Combustor: An Exercise in Verification and Validation

With the simulation of engineering processes via numerical methods on the rise comes the need for a quantitative measure of the agreement between computational results and experimental measurements. The use of quantitative methods in the comparison of the results of numerical and experimental analyses supersedes the traditional qualitative approach. In the present paper, the importance of the role of modeling assumptions in a verification and validation effort is illustrated through a mesoscale combustor example. The various types of uncertainties encountered in the experimentation and numerical simulation are investigated. Through the investigation the initial modeling assumptions proved to be insufficient, producing a comparison error outside of the acceptable range. Thus, the modeling assumptions were sequentially revised, minimizing the comparison error and producing a successful verification and validation effort.

CFD Simulation of a Meso-Scale Combustor: An Exercise in Verification and Validation

With the simulation of engineering processes via numerical methods on the rise comes the need for a quantitative measure of the agreement between computational results and experimental measurements. The use of quantitative methods in the comparison of the results of numerical and experimental analyses supersedes the traditional qualitative approach. In the present paper, the importance of the role of modeling assumptions in a verification and validation effort is illustrated through a meso-scale combustor example. The various types of uncertainties encountered in the experimentation and numerical simulation are investigated. Through the investigation the initial modeling assumptions proved to be insufficient, producing a comparison error outside of the acceptable range. Thus, the modeling assumptions were sequentially revised, minimizing the comparison error and producing a successful verification and validation effort.