Faculty of Mechatronics

Two-dimensional digital image correlation (DIC) is a well established algorithm for quantitative in-plane deformation measurement of a planar object surface in the field of experimental mechanics. Its results provide full-field displacements, often with sub-pixel accuracy. In this paper, we present means to improve speed of calculation for this algorithm using OpenCL to allow computation of very large and precise analysis on generally available hardware (both GPU and CPU). We provide an approach to speed-up the computation of correlations along with discussion and analysis on how each optimization behaves. Thus everyone can pick his own set of optimization that suit best his needs and his concrete algorithm implementation. Our findings can be used both for 2D and 3D variant of DIC algorithm.

Two-dimensional digital image correlation (DIC) is a well-established algorithm for quantitative in-plane deformation measurement of a planar object surface in the field of experimental mechanics. Its results provide full-field displacements, often with sub-pixel accuracy. In this paper, we study possibilities to reduce memory transfers from main computer memory to GPU memory, which could lead to improved computation speeds. We have tested and compared multiple data generation variants for both subset and deformation data. The results show that improvement can be achieved (up to 2.5 times faster), but it depends on concrete type of kernel and optimization used.

Two-dimensional digital image correlation (DIC) is a well-established algorithm for quantitative in-plane deformation measurement of a planar object surface in the field of experimental mechanics. Its results provide full-field displacements, often with sub-pixel accuracy. In this paper, we test and study if it is possible to improve result quality via input image pre-processing. We test multiple image enhancing algorithms and check if the results have improved.

Two-dimensional digital image correlation (DIC) is a well-established algorithm for quantitative in-plane deformation measurement of a planar object surface in the field of experimental mechanics. Its results provide full-field displacements, often with sub-pixel accuracy. The algorithm is a good candidate for parallel computation, both using threads and GPU for computation. While GPUs are very good for parallel computation, it can be quite hard to develop a solution, which will be optimal on all available computation devices and input data configurations. In this paper we explore the possibility to dynamically generate the computation kernel to achieve best performance in all cases.

Background Nanoscale zero-valent iron (nZVI) is commonly used for remediation of groundwater contaminated by chlorinated ethenes (CEs); however, its long-term reactivity and subsurface transport are limited. A novel nZVI–AC material, consisting of colloidal activated carbon (AC) with embedded nZVI clusters, was developed with the aim of overcoming the limitations of nZVI alone. Results Application of a limited amount of nZVI–AC to an oxic, nitrate-rich, highly permeable quaternary aquifer triggered time-limited transformation of CEs, with noticeable involvement of reductive dechlorination. Reductive dechlorination of CEs was dominantly abiotic, as an increase in the concentration of vinyl chloride (VC) and ethene did not coincide with an increase in the abundance of reductive biomarkers for complete dechlorination of CEs (Dehalococcoides, Dehalogenimonas, VC reductase genes vcrA and bvcA). Application of nZVI–AC under unfavourable hydrochemical conditions resulted in no dramatic cha...

This study evaluated the efficiency of two biofilter systems, with and without biochar chambers installed, at degrading and removing HCH and its isomers in natural drainage water. The biochar biofilter proved to be 96% efficient at cleaning HCH and its transformation products from drainage water, a significant improvement over classic biofilter that remove, on average, 68% of HCH. Although iron- and sulfur-oxidizing bacteria, such as Gallionella and Sulfuricurvum, were dominant in the biochar bed outflows, they were absent in sediments, which were rich in Simplicispira, Rhodoluna, Rhodoferax, and Flavobacterium. The presence of functional genes involved in the biodegradation of HCH isomers and their byproducts was confirmed in both systems. The high effectiveness of the biochar biofilter displayed in this study should further encourage the use of biochar in water treatment solutions, e.g., for temporary water purification installations during the construction of other long-term wast...

A stall of cis-1,2-DCE and vinyl chloride (VC) is frequently observed during bioremediation of groundwater chloroethenes via reductive dechlorination. These chloroethenes may be oxidised by aerobic methanotrophs or ethenotrophs co-metabolically and/or metabolically. We assessed the potential for such oxidation at 12 sites (49 groundwater samples) using hydrochemical and molecular biological tools. Both ethenotroph (etnC and etnE) and methanotroph (mmoX and pmoA) functional genes were identified in 90% of samples, while reductive dehalogenase functional genes (vcrA and bvcA) were identified in 82%. All functional genes were simultaneously detected in 78% of samples, in actively biostimulated sites in 88% of samples. Correlation analysis revealed that cis-1,2-DCE concentration was positively correlated with vcrA, etnC and etnE, while VC concentration was correlated with etnC, etnE, vcrA and bvcA. However, feature selection based on random forest classification indicated a significant ...

Clostridioides difficile is the most common pathogen responsible for hospital-acquired diarrhea. This complication of antibiotic treatment mainly endangers the health of elder patients. Preventing the development of C. difficile infections (CDI) is still a challenge that needs to be addressed. In our study, the results of 872 C. difficile positive stool samples were used to describe the epidemiological situation affected by a change in the prescription of fluoroquinolone antibiotics. In a total, 93 of strains were typed by polymerase chain reaction (PCR) and capillary gel electrophoresis. Between years 2014 and 2018 the decline in the fluoroquinolones consumption was 69.3 defined daily dose (DDD) per 1000 patient-days (from 103.3 to 34.0), in same period CDI incidence declined by 1.3 cases per 10,000 patient-bed days (from 5.6 to 4.3). Results of epidemiologic and statistical analysis shows that decline in fluoroquinolones consumption has significant influence on CDI incidence and p...

Clostridioides difficile is the most common pathogen responsible for hospital-acquired diarrhea. This complication of antibiotic treatment mainly endangers the health of elder patients. Preventing the development of C. difficile infections (CDI) is still a challenge that needs to be addressed. In our study, the results of 872 C. difficile positive stool samples were used to describe the epidemiological situation affected by a change in the prescription of fluoroquinolone antibiotics. In a total, 93 of strains were typed by polymerase chain reaction (PCR) and capillary gel electrophoresis. Between years 2014 and 2018 the decline in the fluoroquinolones consumption was 69.3 defined daily dose (DDD) per 1000 patient-days (from 103.3 to 34.0), in same period CDI incidence declined by 1.3 cases per 10,000 patient-bed days (from 5.6 to 4.3). Results of epidemiologic and statistical analysis shows that decline in fluoroquinolones consumption has significant influence on CDI incidence and p...