Homogeneity Assessment of Asphalt Concrete Base in Terms of a Three-Dimensional Air-Launched Ground Penetrating Radar

Obtaining the required homogeneity, including uniform thickness and density, is very crucial for controlling the quality of flexible asphalt layers. Although non-destructive testing (NDT) methods are time-saving and less labor-intensive, they only provide indirect measurement data under testing area conditions and strongly depend on the explanations by prediction models. In this study, in terms of the three-dimensional air-launched Ground Penetrating Radar (GPR) technique, the dielectric constant of asphalt concrete base with dry conditions in pavements was detected and calculated by different methods (the Coring Method, Reflection Amplitudes Method and Common Mid-Point Method). According to the calculated dielectric constant, the thickness and density of asphalt concrete base were further calculated and assessed. Comparing with the Coring Method, the Common Mid-Point Method was recommended to calculate dielectric constants in order to obtain reliable thickness of asphalt pavement base. Among the Birefringence, Boettcher, Linearity indicator, and Rayleigh models, the Rayleigh model was suggested to predict the density, and the predicted density exhibited a good correlation coefficient with the measured one. Furthermore, by choosing these proper calculation methods, an assessment was successfully conducted to evaluate homogeneity of a constructed field pavement in practice.

Introduction to Statistical Methods for Outlier Detection and Sample Homogeneity Assessment of Reference Materials and Proficiency Test Items

Due to the homogeneity of the product or sample, it will affect whether it meets the scope of application and purpose. For example, the reference materials(RM) produced by the reference material producer(RMP), and the proficiency test items selected by the proficiency testing provider(PTP), in order to ensure the reference materials or proficiency test items have consistent characteristics or comparability, they should be proved to have certain homogeneity. However, before performing homogeneity assessment, it is necessary to measure the characteristic parameters of the reference materials or proficiency test items to obtain a sufficient number of measured values for data analysis, but there may be outliers in the measured values that may affect data analysis and interpretation of the results. Therefore, this article will refer to ASTM E178-16a:2016[1], ISO 5725-2:1994[2], ISO 13528:2015[3], etc., to introduce several outlier detection and homogeneity assessment methods, supplemented by case studies. Finally, this article will remind the precautions for the use of the method, so that readers can choose the appropriate method for use in the actual analysis.

Homogeneity of the selected food mixes

The article presents the results of homogeneity assessments for selected food mixes based on computer image analysis. The study was conducted on müsli and condiment mixes standardly available on the consumer market. A total of 40 different ready-for-use products were analysed. Collected samples from three package of each product were placed in a special chamber and then photographed. Photographs were then subjected to computer image analysis to acquire information on the percentage content of individual components. Homogeneity assessment was based on the contents of a selected component called tracer and the coefficient of variation (CV). Lower CV values (3.02–27.31%) and thus better homogeneity was observed for condiment mixes as compared to müsli mixes (3.57–59.15%). Fourteen of twenty condiment mixes had adequate (acceptable at CV ≤ 10%) mixing degree. For the müsli, only six of the tested mixes had appropriate homogeneity. The presented results are a preliminary to developing an image-based methodology for determining the uniformity of granular dry food mixes.

Development of Impact-Echo Multitransducer Device for Automated Concrete Homogeneity Assessment

A combination of multiple nondestructive testing (NDT) methods speeds up the assessment of concrete and increases the precision. This is why the UIR-Scanner was developed at Warsaw University of Technology. The scanner uses an Impact-Echo (IE) method with a unique arrangement of multiple transducers. This paper presents the development of the IE module using numerical models validated with experimental testing. It was found that rectangular arrangement of four transducers with the impactor in the middle is optimal for quick scanning of area for faults and discontinuities, changing the method from punctual to volumetric. A numerical study of void detectability depending on its position with respect to the IE module is discussed as well. After confirmation of the findings of models using experimental tests, the module was implemented into the scanner.

Interest Rate Spread as the 'Power of Growth' on Financial Profitability of Banks in Africa

The high-interest rate has postured solemn distresses to the administration, managers, firms, and the masses. Commercial banks in Africa, principally, are exasperated to use the policy rate to bring down loaning charges. Interest rate charges though have sustained to persist gluey downwards. This study considered the impact of interest rate as the power of growth on financial profitability and examine the causal link amid the measurement variables (bank credit, savings, non-performing loans, and interest rate) between 2000 and 2016. The countries used in this study were investigated as a whole panel and individually per country. First, considering the results from homogeneity assessment and Pesaran CD's checks, we detect the presence of heterogeneity and cross-sectional correlations for the explored data. Second, the CADF and CIPS panel unit root tests report that the variables are non-stationary at their stages but become stationary at their first transformations. Third, the Westerlund-Edgerton panel bootstrap cointegration test shows that the variables are cointegrated and hence possess a structural long-run relationship. Forth, results from the PMG estimator through the panel ARDL model show that; (1) A two-way connectedness is verge by bank credit and FP in the long-period and short-run; (2) A positive and significant one-way cause running from NPLs to BC, a one-way cause amid interest rate and bank credit and lastly one-way causality only in the long-period for NPLs and SAV are evidenced; (3) The PMG estimator through the panel ARDL framework is evidenced to be very significantly effective to the application of Granger causatives test. Though different parameter estimates are evidenced, the results are generally consistent with that of the PMG in terms of connections.