Activiteit

The paper proposed a novel hardware (FPGA) implementation of the coherent averaging architecture for the reconfigurable ultrasonic NDT system. The proposed hardware architecture uses the addressing based shifting technique for the addition operation and Radix-2 non-restoring algorithm for the division operation. Since the amount of hardware required by the proposed averaging scheme is independent of the number of averages, it supports on-the-fly control on the number of averages. Compared to conventional architecture, it provides 96% reduction in memory storage, 98% reduction in the number of adders, and 32% reduction in the processing time for the case of 64 coherent averages. For the experimentation, the ultrasonic imaging system designed and developed by the authors has been utilized. The developed system further supports dynamic on-line reconfiguration of the analog front-end hardware, real-time data acquisition, real-time hardware based data processing, and data transfer operations. The performance of implemented coherent averaging has been presented by various applications such as removal of RF random false-echoes, smoothing of A-scan waveforms and speckle removal of B-scan images. Following the novel introduced concept of the active carriers, this paper brings forward a technique toward the manipulability of an internally piezo-equipped active spherical carrier subjected to the progressive acoustic plane waves as the handling contactless asset. It is assumed that the piezoelectric part of the active carrier may be actuated as a bi-sectional body (i.e., two continuous hemispherical parts), with prescribed phase difference, and the polar position of the imaginary separating plane may be altered. This issue brings about an asymmetry in the dynamics of the problem which leads to emergence of position/frequency dependent acoustic radiation torque. It is obtained that as the carrier is excited by imposing harmonic voltage with the same amplitude and a π-radians phase difference, the zero-radiation force situation is obtained for a specific amplitude and phase of voltage as a function of frequency. This situation is treated as a criterion to determine the optimal amplitude of operation voltage. It is shown that the net force’s direction exerted on the activated carrier may be steered along any desired orientation, assuming the fixed direction of incident wave field. The explained method of excitation and controllability of the spatial position of the divisor plane can possibly be a breakthrough in acoustic handling of active carriers. Noticeably, by this new technique, the single beam acoustic based contact-free methods and their applications in association with the concept of active carriers are now one step forward. V.7-Hydroxy-3,7-dimethyl-1-octanal, also known as 7-hydroxycitronellal (7-HC, CAS No. UAMC-3203 107-75-5) is a synthetic fragrance widely used in cosmetic and hygiene products. Because of its wide spread use and its known sensitizing properties, 7-HC was selected as one of 50 chemicals within the frame of the cooperation project between the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) and the German Chemical Industry Association (VCI) to develop a suitable human biomonitoring (HBM) method in order to assess the exposure of the general population in Germany. Within this scope, the recently published analytical method for urinary 7-hydroxycitronellylic acid (7-HCA), the major metabolite of 7-HC, was applied to 329 24h-urine samples of young adults (20 to 29 years) collected between 2000 and 2018 and stored in the Environmental Specimen Bank (ESB). The widespread exposure to 7-HC as already observed in a pilot study with 40 volunteers could be confirmed with quantifiable concentry applying the described methodology to the representative cohort of the launched German Environmental Survey in adults (GerES VI). Glycol ethers are an oxygenated solvent family widely present in consumer products. Some of them are recognized reproductive, developmental or hematological toxicants. Although several glycol ether biomonitoring studies have been performed on adults from working or general populations, no studies have hitherto been carried out on children. The aim of our study was to explore the detection of glycol ether metabolites in the urinary samples of 6-year-old children, and if any were found, to describe them. The PELAGIE mother-child cohort included 3421 pregnant women from the general population of Brittany, France, between 2002 and 2006. Our biomonitoring study included a random sample of 110 children from the PELAGIE cohort who had participated in a neurodevelopment evaluation at the age of six. First morning voids were collected from all of the children. Eight urinary glycol ether metabolites were measured using gas chromatography with mass spectrometry. The limit of detection was 0.003 mg/L for all metabolites. Glycol ether metabolites were detected at rates varying from 33.5% of samples for propoxyacetic acid to 100% of samples for phenoxyacetic acid and methoxyacetic acid. The highest median concentration observed was for phenoxyacetic acid (0.141 mg/l). Our study reported the ubiquitous presence of glycol ether metabolites in children’s urinary samples. These results call for larger biomonitoring surveys of the general population and study of the potential sources and determinants of these exposures. Safety performance function (SPF) has been a vital tool in traffic safety evaluation including finding contributing factors to crashes, identifying hotspots, and assessing safety effects of countermeasures. In the United States (U.S.), the Highway Safety Manual provides a number of SPFs for a variety of road facilities. Due to the limited availability of traffic data in many regions, the transferability of SPFs has been an important topic in traffic safety analysis and has been evaluated by several studies. Nevertheless, the international transferability of freeway SPFs and the applicability of transferred SPFs on hotspot identification has been rarely investigated. Based on data from two Chinese cities, Shanghai and Suzhou, and three U.S. states, Texas, New York and Florida, this study analyzes the transferability of freeway SPFs between Chinese and U.S. regions. These SPFs are then transferred to the other country and their performance on hotspot identification is investigated. SPFs were developed in the frameworks of Poisson, Poisson-lognormal and negative binomial regressions for the five localities separately, and were calibrated using the calibration functions before being transferred.