158 research outputs found
Bicycle Rider Control: Observations, Modeling & Experiments
No full textBicycle designers traditionally develop bicycles based on experience and trial and error. Adopting modern engineering tools to model bicycle and rider dynamics and control is another method for developing bicycles. This method has the potential to evaluate the complete design space, and thereby develop well handling bicycles for specific user groups in a much shorter time span. The recent benchmarking of the Whipple bicycle model for the balance and steer of a bicycle is an opening enabling the accurate modeling of a bicycle and making this engineering route very viable. However the route also requires a rider model in order to be successful, but at present, very little is known about the bicycle rider. The aim of this work is to get a step closer to being able to determine a-priori the handling qualities of bicycles and thereby enable the development of better, safer and out of the ordinary bicycles. To this end observation experiments have been performed to discover what control actions a rider performs on a bicycle and observed rider motions have then been implemented in a passive rider model. Furthermore the almost universally accepted requirements for bicycle self stability of spin angular momentum (gyroscopic effect) and trail have been shown experimentally to not be necessary.Precision and Microsystems EngineeringMechanical, Maritime and Materials Engineerin
Coarse-grained Ginzburg-Landau free energy for Lennard-Jones systems
No full textIn this study, self-consistent coarse-graining scheme was used in conjunction with molecular dynamic (MD) simulation to determine the parameters in a Ginzburg-Landau free energy function for a system described by the Lennard-Jones potential. The dependence of these parameters on temperature and chemical potential was determined by reweighting multivariate histograms compiled in a single thermodynamic state. As a result, a link was established between the atomistic and mesoscopic length scales.This work was supported by the NSF under Grants Nos. DMR-9813409 and DMR-9975384. One of us (J.D.G) wishes to thank Iberdrola for their support during part of this project. We also wish to acknowledge an allocation of time from the PSC Supercomputing Center.Peer Reviewe
Balance and control of a rear-wheel steered speed-record recumbent bicycle
No full textThe goal of the Human Power Team from the TU Delft and the Free University of Amsterdam is to break the world speed record in unpaced cycling (Sam Whittingham, 133.28 km/h). The design of such a faired recumbent bicycle is a challenge. The Delft design, called VeloX (Human Power Team (2013)), is a fully-faired monocoque front-driven recumbent bicycle, with minimized air drag and maximized space for a big and strong athlete. However, front driven bicycles have the disadvantage that the front driving induces unwanted steering and that the frontal area of the bicycle cannot be reduced any further. A solution would be rear-wheel steering. A common thought is that a rear-wheel steered bicycle cannot be laterally self-stable, and therefore hard to control. However, recent research (Knoll et al. (2012)) has shown that one can design a rear-wheel steered bicycle which shows a stable forward speed range. Based on these results a rear-wheel steered recumbent bicycle has been designed, within the existing design constraints. Although not self-stable, this design shows a mildly lateral unstable behavior in the desired forward speed range of 0 to 40 m/s (0 to 144 km/h). Computer simulations demonstrate that the bicycle can be stabilized by adding a human controller model (Schwab et al. (2013)) to the bicycle model. For a set of expected lateral perturbations (side wind perturbations) it is shown that rider steer torque stays within human bounds, both in magnitude and in frequency. Future work is dedicated to building and testing a prototype of the design.Biomechanical EngineeringMechanical, Maritime and Materials Engineerin
A pentangular plant inflammasome
No full textLike animals, plants require, and have evolved, a robust innate immune system. Plants can detect and respond to pathogen-derived molecules (effectors) through cell surface receptors and intracellular receptors, typically encoded by disease resistance (R) genes. Analysis of plant genome sequences reveals hundreds of such nucleotide-binding, leucine-rich repeat (NLR) proteins encoded by putative R genes. How such NLR proteins function has long been a matter of speculation. On page 43 and 44 of this issue, Wang et al. and Wang et al., respectively, end much of the speculation by defining the mechanism of activation for at least one NLR, the Arabidopsis thaliana HOPZ-ACTIVATED RESISTANCE 1 (ZAR1) protein, which activates defense in response to several pathogenic bacterial effectors
The Ncm-1 gene for resistance to Cucumber mosaic virus in yellow lupin (Lupinus luteus): molecular studies and marker development
No full textCucumber mosaic virus (CMV) is an important virus pathogen of lupins in Australia which causes serious yield losses of up to 60% in epidemic years. In commercially grown lupin (Lupinus angustifolius and L. luteus) crops CMV is spread non-persistently by aphid vectors, but it can also be seed borne and this extends virus infection into successive generations. Resistance to CMV has been identified in L. luteus cv. Wodjil and is the conferred by the Ncm-1 gene. The aims of this research were to study the Ncm-1 gene in order to gain a better understanding of resistance in yellow lupin, and to develop a molecular marker linked to Ncm-1 for use in marker assisted selection.
Previously published data by Jones et al (1996) identified Ncm-1 as being a single dominant resistance gene, however, phenotypic analysis of CMV infection in a segregating L. luteus mapping population in this thesis was consistent with the Ncm-1 gene being a dominant gene modified by at least one other minor gene. The polygenic nature of CMV resistance in this genetic background was further supported by AFLP analysis which identified one major and one minor QTL associated with resistance.
A PCR based approach, using degenerate primers designed on conserved disease resistance protein motifs, was used to identify resistance gene analogues (RGA) in L. luteus. Comparative analysis revealed that RGAs isolated from L. luteus were members of the TIR-NBS-LRR class of R proteins and were similar to the TMV resistance gene N identified in tobacco and the RT4-4 CMV resistance gene from pepper. Extensive comparative analysis using the genomes of model species (including Medicago truncatula, Glycine max, Arabidopsis thaliana and Lotus japonicus) was explored and validated the assignment from L. luteus RGAs to the category of candidate gene for CMV resistance. The RGAs identified in L. luteus were found to be highly conserved in both the CMV resistant and susceptible varieties tested. SNPs which resulted in non-synonymous mutations were identified using cDNA based 5’ RACE and used to develop a single nucleotide primer extension (SNuPE) assays for MALDI-ToF mass spectrophotometric analysis. As SNuPE is based on the allele specific extension of a single nucleotide, genotyping is highly accurate and provides co-dominant information. Two SNuPE assays were developed based on the RGAs isolated and validated on bulked samples from two L.luteus populations segregating for CMV resistance. One assay, SNuPE A267→C was found to associate with CMV resistance. This co-dominant assay is the first of its kind reported for yellow lupin
Rider motion identification during normal bicycling by means of principal component analysis
No full textRecent observations of a bicyclist riding through town and on a treadmill show that the rider uses the upper body very little when performing normal maneuvers and that the bicyclist may, in fact, primarily use steering input for control. The observations also revealed that other motions such as lateral movement of the knees were used in low speed stabilization. In order to validate the hypothesis that there is little upper body motion during casual cycling, an in-depth motion capture analysis was performed on the bicycle and rider system. We used motion capture technology to record the motion of three similar young adult male riders riding two different city bicycles on a treadmill. Each rider rode each bicycle while performing stability trials at speeds ranging from 2 km/h to 30 km/h: stabilizing while pedaling normally, stabilizing without pedaling, line tracking while pedaling, and stabilizing with no-hands. These tasks were chosen with the intent of examining differences in the kinematics at various speeds, the effects of pedaling on the system, upper body control motions and the differences in tracking and stabilization. Principal component analysis was used to transform the data into a manageable set organized by the variance associated with the principal components. In this paper, these principal components were used to characterize various distinct kinematic motions that occur during stabilization with and without pedaling. These motions were grouped on the basis of correlation and conclusions were drawn about which motions are candidates for stabilization-related control actions.Precision and Microsystems EngineeringMechanical, Maritime and Materials Engineerin
Nauczanie św. Pawła odnośnie do charyzmatów
No full textThe presentation of the reality related to charisms in Old Testament , The Gospels and Acts of the Apostoles, discussed the primary meaning and occurrence of the words „charism/charisms” in the Bible. Against this background, author draws the direct context of the teaching of charisms by discussing the Corinthian community and First Corinthians. In his analysis, he focuses on the section concerned with spiritual reality (1 Corinthians 12–14), showing various forms of charisms functioning within the Church portrayed as the body of Christ. He captures the connections between charisms and love and also the practise of glossolalia and prophecy. The whole is completed by discussing the analysis of St. Paul’s teaching about charisms made in various articles by Käsemann, R.Y.K. Fung, G.D. Fee, J.D.G. Dunn.G. Barbaglio.Po przedstawieniu rzeczywistości dotyczącej charyzmatów w Starym Testamencie, w Ewangeliach, Dziejach Apostolskich zostało omówione pierwotne znaczenie i występowanie słów „charyzmat/charyzmaty” w Biblii. Na tym tle autor rysuje bezpośredni kontekst nauczania o charyzmatach omawiając wspólnotę Koryncką i Pierwszy List do Koryntian. W swoich analizach koncentruje się na sekcji dotyczącej rzeczywistości duchowej (1 Kor 12–14) ukazując różne funkcjonowanie charyzmatów wewnątrz Kościoła przedstawionego jako ciało Chrystusa. Ujmuje zależności pomiędzy charyzmatami a miłością oraz praktykowaniem glosolalii i proroctwa. Całość dopełnia omówienie analiz dotyczących nauczania św. Pawła o charyzmatach dokonanych w różnych artykułach przez Käsemann, R.Y.K. Fung, G.D. Fee, J.D.G. Dunn. G. Barbaglio
Thirty years of resistance: zig-zag through the plant immune system
No full textUnderstanding the plant immune system is crucial for using genetics to protect crops from diseases. Plants resist pathogens via a two-tiered innate immune detection-and-response system. The first plant Resistance (R) gene was cloned in 1992 (Johal and Briggs, 1992). Since then, many cell-surface pattern recognition receptors (PRRs) have been identified, and R genes that encode intracellular nucleotide-binding leucine-rich repeat receptors (NLRs) have been cloned. Here, we provide a list of characterized PRRs and NLRs. In addition to immune receptors, many components of immune signaling networks were discovered over the last 30 years. We review the signaling pathways, physiological responses, and molecular regulation of both PRR- and NLR-mediated immunity. Recent studies have reinforced the importance of interactions between the two immune systems. We provide an overview of interactions between PRR- and NLR-mediated immunity, highlighting challenges and perspectives for future research.Plant science
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