82 research outputs found
Genetic programming for fiber-threading for fiber-reinforced plastics
Setting up fiber-threading for a pultrusion line is tedious, error prone and takes a long time. Between 100 and 1000 fibers have to be arranged into a two-dimensional shape, which have to be threaded between several support plates without causing crossovers. When manually planning this process based on intuition, it is hard to keep track of the complexity. This slows the process down to where it can take several hours or several days, and shortening this duration reduces the cost considerably. As planning the setup takes up a large chunk of time, we are proposing a simulation and an algorithm to automatically calculate how the fiber bundles need to be threaded from the creels through the support plates to result in the desired shape. Using a three-dimensional simulation for collision detection in conjunction with a genetic algorithm, we are able to shorten the planning of the fibers to around 10 minutes on a modern 8-core personal computer. Based on this data, further work can be done to further improve, visualize or permanently store the data in a digitized company
Laser-induced forward transfer as a versatile tool for developing silicon-based anode materials
Further efforts are needed to increase the power and energy density of lithium-ion batteries. This increase can be achieved by developing new electrode architectures and new active materials. As a new active material for anodes, silicon is in the focus of current research, as it has an order of magnitude higher specific energy density compared to the commonly used graphite. In terms of new architecture, printing anodes with the "laser induced forward transfer" (LIFT) process offers a variety of possibilities. For this work, printing with LIFT adapted anode paste was realized and corresponding laser parameters were optimized. The anodes were printed with graphite for subsequent analyses in a coin cell and compared with state-of-the-art coated electrodes made with the same paste. The conventional coated electrodes were either calendered or uncalendered. It was shown that the electrochemical behavior of the printed anodes is comparable to that of the conventional coated anodes. Finally, preliminary studies were made to print an anode with a multilayer architecture. Within the anode layer, which consists of three individual printed layers, silicon layers are incorporated in order to significantly increase the specific capacity
Laser-induced forward transfer as a versatile tool for developing silicon-based anode materials
Further efforts are needed to increase the power and energy density of lithium-ion batteries. This increase can be achieved by developing new electrode architectures and new active materials. As a new active material for anodes, silicon is in the focus of current research, as it has an order of magnitude higher specific energy density compared to the commonly used graphite. In terms of new architecture, printing anodes with the "laser induced forward transfer" (LIFT) process offers a variety of possibilities. For this work, printing with LIFT adapted anode paste was realized and corresponding laser parameters were optimized. The anodes were printed with graphite for subsequent analyses in a coin cell and compared with state-of-the-art coated electrodes made with the same paste. The conventional coated electrodes were either calendered or uncalendered. It was shown that the electrochemical behavior of the printed anodes is comparable to that of the conventional coated anodes. Finally, preliminary studies were made to print an anode with a multilayer architecture. Within the anode layer, which consists of three individual printed layers, silicon layers are incorporated in order to significantly increase the specific capacity
Synthesis of ZIF-11 Membranes: The Influence of Preparation Technique and Support Type
Due to its structural features, ZIF-11 is one of the most interesting materials for gas separation applications. Herein, we report a systematic study on the synthesis of ZIF-11 as a supported membrane. For this, we adapted optimized conditions for the ZIF-11 powder synthesis, identified in our previous works, to form ZIF layers on symmetric and asymmetric stainless-steel and asymmetric α-Al2O3 supports. Different techniques were investigated for the challenging layer formation, namely, in situ crystallization (ISC), multiple in situ crystallization (MISC), and the seeding and secondary growth (SSG) method. It was possible to deposit ZIF-11 on different supports by ISC and MISC, although it was difficult to obtain complete layers. SSG, in turn, was more effective in forming dense and well-intergrown ZIF-11 layers. This agrees well with the generally accepted fact that seeding considerably facilitates layer formation. Systematic studies of both individual steps of SSG (seeding and secondary growth) led to a basic understanding of layer formation of ZIF-11 on the different supports. The best membranes prepared by rub seeding and secondary growth achieved Knudsen selectivity. Improved gas separation performance is expected if the formation of defects can be avoided
Bipolar disorder risk alleles in children with ADHD
Bipolar disorder (BD) and attention deficit/hyperactivity disorder (ADHD) may share common genetic risk factors as indicated by the high co-morbidity of BD and ADHD, their phenotypic overlap especially in pediatric populations, the high heritability of both disorders, and the co-occurrence in families. We therefore examined whether known polygenic BD risk alleles are associated with ADHD. We chose the eight best SNPs of the recent genome-wide association study (GWAS) of BD patients of German ancestry and the nine SNPs from international GWAS meeting a ‘genome-wide significance' level of α=5×10−8. A GWAS was performed in 495 ADHD children and 1,300 population-based controls using HumanHap550v3 and Human660W-Quadv1 BeadArrays. We found no significant association of childhood ADHD with single BD risk alleles surviving adjustment for multiple testing. Yet, risk alleles for BD and ADHD were directionally consistent at eight of nine loci with the strongest support for three SNPs in or near NCAN, BRE, and LMAN2L. The polygene analysis for the BP risk alleles at all 14 loci indicated a higher probability of being a BD risk allele carrier in the ADHD cases as compared to the controls. At a moderate power to detect association with ADHD, if true effects were close to estimates from GWAS for BD, our results suggest that the possible contribution of BD risk variants to childhood ADHD risk is considerably lower than for BD. Yet, our findings should encourage researchers to search for common genetic risk factors in BD and childhood ADHD in future studie
Bipolar disorder risk alleles in children with ADHD
Bipolar disorder (BD) and attention deficit/hyperactivity disorder (ADHD) may share common genetic risk factors as indicated by the high co-morbidity of BD and ADHD, their phenotypic overlap especially in pediatric populations, the high heritability of both disorders, and the co-occurrence in families. We therefore examined whether known polygenic BD risk alleles are associated with ADHD. We chose the eight best SNPs of the recent genome-wide association study (GWAS) of BD patients of German ancestry and the nine SNPs from international GWAS meeting a 'genome-wide significance' level of α = 5 × 10(-8). A GWAS was performed in 495 ADHD children and 1,300 population-based controls using HumanHap550v3 and Human660 W-Quadv1 BeadArrays. We found no significant association of childhood ADHD with single BD risk alleles surviving adjustment for multiple testing. Yet, risk alleles for BD and ADHD were directionally consistent at eight of nine loci with the strongest support for three SNPs in or near NCAN, BRE, and LMAN2L. The polygene analysis for the BP risk alleles at all 14 loci indicated a higher probability of being a BD risk allele carrier in the ADHD cases as compared to the controls. At a moderate power to detect association with ADHD, if true effects were close to estimates from GWAS for BD, our results suggest that the possible contribution of BD risk variants to childhood ADHD risk is considerably lower than for BD. Yet, our findings should encourage researchers to search for common genetic risk factors in BD and childhood ADHD in future studies
Construction and validation of the Touch Experiences and Attitudes Questionnaire (TEAQ): a self-report measure to determine attitudes to and experiences of positive touch
Despite growing interest in the beneficial effects of positive touch experiences throughout our lives, and individual differences in how these experiences are perceived, a contemporary self-report measure of touch experiences and attitudes for which the factor structure has been validated, is as yet not available. This article describes four studies carried out during the construction and validation of the Touch Experiences and Attitudes Questionnaire (TEAQ). The original TEAQ, containing 117 items relating to positive touch experiences was systematically constructed. Principal component analysis reduced this measure to 57 items and identified six components relating to touch experiences during childhood (ChT) and adult experiences relating to current intimate touch (CIT) and touch with friends and family (FFT). Three attitudinal components were identified, relating to attitude to intimate touch (AIT), touch with unfamiliar people (AUT) and self-care (ASC). The structure of this questionnaire was confirmed through confirmatory factor analysis carried out on data obtained from a second sample. Good concurrent and predictive validity of the TEAQ compared to other physical touch measures currently available was identified. Known-group validity in terms of gender, marital status and age was determined, with expected group differences identified. This study demonstrates the TEAQ to have good face validity, internal consistency, construct validity in terms of discriminant validity, known-group validity and convergent validity, and criterion-related validity in terms of predictive validity and concurrent validity. We anticipate this questionnaire will be a valuable tool for the field of physical touch research
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