11,742 research outputs found
The anomalous current multiplet in 6D minimal supersymmetry
For supersymmetric gauge theories with eight supercharges in four, five and
six dimensions, a conserved current belongs to the linear multiplet. In the
case of six-dimensional Poincar\'e supersymmetry, we present a
consistent deformation of the linear multiplet which describes chiral
anomalies. This is achieved by developing a superform formulation for the
deformed linear multiplet. In the abelian case, we compute a nonlocal effective
action generating the gauge anomaly.Comment: 27 pages; V2: published versio
Chiral anomalies in six dimensions from harmonic superspace
We develop a superfield approach to compute chiral anomalies in general
supersymmetric gauge theories in six dimensions. Within the
harmonic-superspace formulation for these gauge theories, the anomalous
contributions to the effective action only come from matter and ghost
hypermultiplets. By studying the short-distance behaviour of the propagator for
the hypermultiplet coupled to a background vector multiplet, we compute the
covariant and consistent chiral anomalies. We also provide a superform
formulation for the non-abelian anomalous current multiplet in general supersymmetric gauge theories.Comment: 33 page
An Intelligent System for Structural Analysis-Based Design Improvements
The goal of the research work presented in this paper was to collect, organize, and write the knowledge and experience about structural analysis-based design improvements into a knowledge base for a consultative advisory intelligent decision support system. The prototype of the system presented proposes possible design changes that should be taken into consideration to improve the design candidate according to the results of a prior stress-strain or thermal analysis. The system can be applied either in the design of new products or as an educational tool.
Galaxy size trends as a consequence of cosmology
We show that recently documented trends in galaxy sizes with mass and
redshift can be understood in terms of the influence of underlying cosmic
evolution; a holistic view which is complimentary to interpretations involving
the accumulation of discreet evolutionary processes acting on individual
objects. Using standard cosmology theory, supported with results from the
Millennium simulations, we derive expected size trends for collapsed cosmic
structures, emphasising the important distinction between these trends and the
assembly paths of individual regions. We then argue that the observed variation
in the stellar mass content of these structures can be understood to first
order in terms of natural limitations of cooling and feedback. But whilst these
relative masses vary by orders of magnitude, galaxy and host radii have been
found to correlate linearly. We explain how these two aspects will lead to
galaxy sizes that closely follow observed trends and their evolution, comparing
directly with the COSMOS and SDSS surveys. Thus we conclude that the observed
minimum radius for galaxies, the evolving trend in size as a function of mass
for intermediate systems, and the observed increase in the sizes of massive
galaxies, may all be considered an emergent consequence of the cosmic
expansion.Comment: 14 pages, 13 figures. Accepted by MNRA
Development of bio-based chitosan films with incorporated chestnut extract
Hydrolysable tannins have prominent biological activity and thus their industrial application is gaining importance in many fields. This study explored the possibility for the utilization of a commercially available chestnut extract (CE) as an active component in chitosan-based films intended for food packaging. Therefore, a set of chitosan-based films with incorporated CE was prepared and evaluated regarding physicochemical properties. The estimated total phenolic content (TPC) has revealed a maximal value of 19.5 mgGAE gfilm-1. Moreover, the moisture content (MC) in the films has decreased (from 29.6% to 18.6%), while tensile strength (TS) has increased (from 13.5 MPa to 48.5 MPa) after the incorporation of CE. The observed coherence between TPC and evaluated properties has been confirmed by the existence of strong negative and positive linear correlations in the case of MC and TS, respectively. In large, CE extract was found to be a promising candidate as an active component in chitosan-based films
Intelligent Support for a Computer Aided Design Optimisation Cycle
It is becoming more and more evident that adding intelligence to existing computer aids, such as computer aided design systems, can lead to significant improvements in the effective and reliable performance of various engineering tasks, including design optimisation. This paper presents three different intelligent modules to be applied within a computer aided design optimisation cycle to enable more intelligent and less experience-dependent design performance.
Improved shaping approach to the preliminary design of low-thrust trajectories
This paper presents a general framework for the development of shape-based approaches to low-thrust trajectory design. A novel shaping method, based on a three-dimensional description of the trajectory in spherical coordinates, is developed within this general framework. Both the exponential sinusoid and the inverse polynomial shaping are demonstrated to be particular two-dimensional cases of the spherical one. The pseudoequinoctial shaping is revisited within the new framework, and the nonosculating nature of the pseudoequinoctial elements is analyzed. A two step approach is introduced to solve the time of flight constraint, related to the design of low-thrust arcs with boundary constraints for both spherical and pseudoequinoctial shaping. The solution derived from the shaping approach is improved with a feedback linear-quadratic controller and compared against a direct collocation method based on finite elements in time. The new shaping approach and the combination of shaping and linear-quadratic controller are tested on three case studies: a mission to Mars, a mission to asteroid 1989ML, a mission to comet Tempel-1, and a mission to Neptune
Sensitivity to the KARMEN Timing Anomaly at MiniBooNE
We present sensitivities for the MiniBooNE experiment to a rare exotic pion
decay producing a massive particle, Q^0. This type of decay represents one
possible explanation for the timing anomaly reported by the KARMEN
collaboration. MiniBooNE will be able to explore an area of the KARMEN signal
that has not yet been investigated
Low-cost wearable multichannel surface EMG acquisition for prosthetic hand control
Prosthetic hand control based on the acquisition
and processing of surface electromyography signals (sEMG) is a
well-established method that makes use of the electric potentials
evoked by the physiological contraction processes of one or more
muscles. Furthermore intelligent mobile medical devices are on
the brink of introducing safe and highly sophisticated systems to
help a broad patient community to regain a considerable amount
of life quality. The major challenges which are inherent in such
integrated system’s design are mainly to be found in obtaining a
compact system with a long mobile autonomy, capable of
delivering the required signal requirements for EMG based
prosthetic control with up to 32 simultaneous acquisition
channels and – with an eye on a possible future exploitation as a
medical device – a proper perspective on a low priced system.
Therefore, according to these requirements we present a wireless,
mobile platform for acquisition and communication of sEMG
signals embedded into a complete mobile control system
structure. This environment further includes a portable device
such as a laptop providing the necessary computational power
for the control and a commercially available robotic handprosthesis.
Means of communication among those devices are
based on the Bluetooth standard. We show, that the developed
low cost mobile device can be used for proper prosthesis control
and that the device can rely on a continuous operation for the
usual daily life usage of a patient
Reduction in Spoilage Microbiota and Cyclopiazonic Acid Mycotoxin with Chestnut Extract Enriched Chitosan Packaging: Stability of Inoculated Gouda Cheese
Active chitosan-based films, blended with fibrous chestnut (Castanea sativa Mill.) tannin-rich extract were used to pack Gouda cheese that has been contaminated with spoilage microflora Pseudomonas fluorescens, Escherichia coli, and fungi Penicillium commune. A comprehensive experimental plan including active chitosan-based films with (i) chestnut extract (CE), (ii) tannic acid (TA), and (iii) without additives was applied to evaluate the film′s effect on induced microbiological spoilage reduction and chemical indices of commercial Gouda cheese during 37 days while stored at 4 °C and 25 °C, respectively. The cheese underwent microbiology analysis and chemical assessments of ultra-high-performance liquid chromatography (UHPLC) (cyclopiazonic acid), pH, and moisture content. The biopackaging used for packing cheese was characterized by mechanical properties before food packaging and analyzed with the same chemical analysis. The cheese microbiology showed that the bacterial counts were most efficiently decreased by the film without additives. However, active films with CE and TA were more effective as they did not break down around the cheese and showed protective properties against mycotoxin, moisture loss, and pH changes. Films themselves, when next to high-fat content food, changed their pH to less acidic, acted as absorbers, and degraded without plant-derived additives
- …