86 research outputs found

    Towards Real-Time Control of a Semibatch Crystallization Process by Electrical and Ultrasound Tomographic Techniques

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    This research work presents a feasibility study to demonstrate the application of Electrical Resistance Tomography and transmission-based Ultrasound Computed Tomography for monitoring and control of micron-sized calcium carbonate crystallization process. Herein, precipitated calcium carbonate production is bind to a carbon dioxide absorption process based on hollow-fiber membrane contactor.ERT acquisition system is equipped with 16 electrodes with operating frequency of 156 KHz and image capturing frame rate of 2 Hz. The ultrasound tomography equipment consists of 32 piezoelectric transducers at a frequency of 200 KHz. These sensors are sensitive to changes in suspension density and conductivity. Furthermore, a process control framework is developed by utilizing the fundamental relations of settling velocity of particles. Through simulations in the LabVIEW software, the PI-based feedback controller demonstrates a possibility of setpoint tracking by manipulating the control variable (mixing speed). Upon further investigations, this approach can be used as a multi-dimensional process analytical technology tool for quality assurance and malfunction diagnosis when out-of-specification events occur throughout the entire process

    Predominant location of coronary artery atherosclerosis in the left anterior descending artery. The impact of septal perforators and the myocardial bridging effect

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    INTRODUCTION: Coronary artery atherosclerosis presents characteristic patterns of plaque distribution despite systemic exposure to risk factors. We hypothesized that local hemodynamic forces induced by the systolic compression of intramuscular septal perforators could be involved in atherosclerotic processes in the left anterior descending artery (LAD) adjacent to the septal perforators' origin. Therefore we studied the spatial distribution of atherosclerosis in coronary arteries, especially in relation to the septal perforators' origin. MATERIAL AND METHODS: 64-slice computed tomography angiography was performed in 309 consecutive patients (92 male and 217 female) with a mean age of 59.9 years. Spatial plaque distribution in the LAD was analyzed in relation to the septal perforators' origin. Additionally, plaque distribution throughout the coronary artery tree is discussed. RESULTS: The coronary calcium score (CCS) was positive in 164 patients (53.1%). In subjects with a CCS > 0, calcifications were more frequent in the LAD (n = 150, 91.5%) compared with the right coronary artery (RCA) (n = 94, 57.3%), circumflex branch (CX) (n = 76, 46.3%) or the left main stem (n = 42, 25.6%) (p < 0.001). Total CCS was higher in the LAD at 46.1 (IQR: 104.2) and RCA at 34.1 (IQR: 90.7) than in the CX at 16.8 (IQR: 61.3) (p = 0.007). In patients with calcifications restricted to a single vessel (n = 54), the most frequently affected artery was the LAD (n = 42, 77.8%). In patients with lesions limited to the LAD, the plaque was located mostly (n = 37, 88.1%) adjacent to the septal perforators' origin. CONCLUSIONS: We demonstrated that coronary calcifications are most frequently located in the LAD in proximity to the septal branch origin. A possible explanation for this phenomenon could be the dynamic compression of the tunneled septal branches, which may result in disturbed blood flow in the adjacent LAD segment (milking effect)

    A model species for agricultural pest genomics: the genome of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

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    The Colorado potato beetle is one of the most challenging agricultural pests to manage. It has shown a spectacular ability to adapt to a variety of solanaceaeous plants and variable climates during its global invasion, and, notably, to rapidly evolve insecticide resistance. To examine evidence of rapid evolutionary change, and to understand the genetic basis of herbivory and insecticide resistance, we tested for structural and functional genomic changes relative to other arthropod species using genome sequencing, transcriptomics, and community annotation. Two factors that might facilitate rapid evolutionary change include transposable elements, which comprise at least 17% of the genome and are rapidly evolving compared to other Coleoptera, and high levels of nucleotide diversity in rapidly growing pest populations. Adaptations to plant feeding are evident in gene expansions and differential expression of digestive enzymes in gut tissues, as well as expansions of gustatory receptors for bitter tasting. Surprisingly, the suite of genes involved in insecticide resistance is similar to other beetles. Finally, duplications in the RNAi pathway might explain why Leptinotarsa decemlineata has high sensitivity to dsRNA. The L. decemlineata genome provides opportunities to investigate a broad range of phenotypes and to develop sustainable methods to control this widely successful pest

    Numerical study of the shape effect in the ceramic based ballistic panels

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    The numerical investigations have been performed to determine the front surface shape effect in the cer based armour systems. Different shapes of ceramic elements were analyzed, including hemispheres and pyramids with respect to standard flat tiles. The influence of the impact point location was also under considerations. The Computer simulations were performed with the Element Free Galerkin Method (EFG) implemented in LS-D code. An impact of the 14.5xll8mm B32 armour piercing projectile on the A12O3 different shape elements backe 7017 aluminium alloy plate was analyzed. Full 3D models of the projectile and targets were developed with strain, rate and temperature dependent material constitutive relations. The models of the projectile, ceramic and aluminium alloy targets were validated with utilization of the experimental data found in literature. The obtained results confirm, the preliminary presumptions, that the shape of the front surface can significant role in the overall ballistic resistance of the panel. Particularly projectile-target initial contact area st to be important factor as showed by impact point location analysis. The conclusions presented in this paper can be applied to develop modern impact protection panels where the appropriate balance between the mass and protection level must be accomplished
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