Modeling of composite beams and plates for static and dynamic analysis

A rigorous theory and corresponding computational algorithms was developed for a variety of problems regarding the analysis of composite beams and plates. The modeling approach is intended to be applicable to both static and dynamic analysis of generally anisotropic, nonhomogeneous beams and plates. Development of a theory for analysis of the local deformation of plates was the major focus. Some work was performed on global deformation of beams. Because of the strong parallel between beams and plates, the two were treated together as thin bodies, especially in cases where it will clarify the meaning of certain terminology and the motivation behind certain mathematical operations

Modeling of composite beams and plates for static and dynamic analysis

The main purpose of this research was to develop a rigorous theory and corresponding computational algorithms for through-the-thickness analysis of composite plates. This type of analysis is needed in order to find the elastic stiffness constants for a plate and to post-process the resulting plate solution in order to find approximate three-dimensional displacement, strain, and stress distributions throughout the plate. This also requires the development of finite deformation plate equations which are compatible with the through-the-thickness analyses. After about one year's work, we settled on the variational-asymptotical method (VAM) as a suitable framework in which to solve these types of problems. VAM was applied to laminated plates with constant thickness in the work of Atilgan and Hodges. The corresponding geometrically nonlinear global deformation analysis of plates was developed by Hodges, Atilgan, and Danielson. A different application of VAM, along with numerical results, was obtained by Hodges, Lee, and Atilgan. An expanded version of this last paper was submitted for publication in the AIAA Journal

Annual Report 2021 - Institute of Resource Ecology

The Institute of Resource Ecology (IRE) is one of the eight institutes of the Helmholtz-Zentrum Dresden–Rossendorf (HZDR). Our research activities are mainly integrated into the program “Nuclear Waste Management, Safety and Radiation Research (NUSAFE)” of the Helmholtz Association (HGF) and focus on the topics “Safety of Nuclear Waste Disposal” and “Safety Research for Nuclear Reactors”. The program NUSAFE, and therefore all work which is done at IRE, belong to the research field “Energy” of the HGF. IRE conducts applied basic research to protect humans and the environment from the effects of radioactive radiation. For this purpose, we develop molecular process understand-ing using state-of-the-art methods of microscopy, spectroscopy, diffraction, numerical simulation, theoretical chemistry and systems biology. We implement this in a cross-institutional research environment at the HZDR. Our active interdisciplinarity combines radiochemistry, geosciences and biosciences as well as materials science and reactor physics. We provide knowledge that is applied in particular to reactor and repository safety as well as in radioecology. We achieve this goal with a unique infrastructure comprising chemical and biological laboratories as well as hot cells in corresponding radiation and biology safety laboratories in Dresden, Leipzig and Grenoble. In Grenoble, at the European Synchrotron Radiation Facility (ESRF), the institute operates a beamline with four experimental stations for continuously advanced X-ray spectroscopy and diffraction of radio-active samples, which is also available to external users

The Painting Industries of Antwerp and Amsterdam, 1500−1700: A Data Perspective

This study presents a data driven comparative analysis of the painting industries in sixteenth and seventeenth century Antwerp and Amsterdam. The popular view of the development of these two artistic centers still holds that Antwerp flourished in the sixteenth century and was succeeded by Amsterdam after the former’s recapturing by the Spanish in 1585. However, a demographic analysis of the number of painters active in Antwerp and Amsterdam shows that Antwerp recovered relatively quickly after 1585 and that it remained the leading artistic center in the Low Countries, only to be surpassed by Amsterdam in the 1650’s. An analysis of migration patterns and social networks shows that painters in Antwerp formed a more cohesive group than painters in Amsterdam. As a result, the two cities responded quite differently to internal and external market shocks. Data for this study are taken from ECARTICO, a database and a linked data web resource containing structured biographical data on over 9100 painters working in the Low Countries until circa 1725

Analysis of Laser ARPES from Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta} in superconductive state: angle resolved self-energy and fluctuation spectrum

We analyze the ultra high resolution laser angle resolved photo-emission spectroscopy (ARPES) intensity from the slightly underdoped Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ in the superconductive (SC) state. The momentum distribution curves (MDC) were fitted at each energy \w employing the SC Green's function along several cuts perpendicular to the Fermi surface with the tilt angle $\theta$ with respect to the nodal cut. The clear observation of particle-hole mixing was utilized such that the complex self-energy as a function of $\omega$ is directly obtained from the fitting. The obtained angle resolved self-energy is then used to deduce the Eliashberg function \alpha^2 F^{(+)}(\th,\w) in the diagonal channel by inverting the d-wave Eliashberg equation using the maximum entropy method. Besides a broad featureless spectrum up to the cutoff energy $\omega_c$, the deduced $\alpha^2 F$ exhibits two peaks around 0.05 eV and 0.015 eV. The former and the broad feature are already present in the normal state, while the latter emerges only below $T_c$. Both peaks become enhanced as $T$ is lowered or the angle $\th$ moves away from the nodal direction. The implication of these findings are discussed.Comment: 7 pages, 5 figures, summited to PR

Annual Report 2022 - Institute of Resource Ecology

The Institute of Resource Ecology (IRE) is one of the ten institutes of the Helmholtz-Zentrum Dresden – Rossendorf (HZDR). Our research activities are mainly integrated into the program “Nuclear Waste Management, Safety and Ra-diation Research (NUSAFE)” of the Helmholtz Association (HGF) and focus on the topics “Safety of Nuclear Waste Disposal” and “Safety Research for Nuclear Reactors”. The program NUSAFE, and therefore all work which is done at IRE, belong to the research field “Energy” of the HGF

Persistence of insecticidal activity of novel bio-encapsulated formulations of Bacillus thuringiensis var. kurstaki against Choristoneura rosaceana [Lepidoptera: Tortricidae]

Le DiPelTM, une formulation commerciale du Bacillus thuringiensis var. kurstaki (Btk), et des formulations bio-encapsulées du Btk ont été pulvérisées dans un verger de pommiers. Pendant trois années consécutives, leur persistance a été évaluée en laboratoire sur des larves de tordeuse à bandes obliques (Choristoneura rosaceana). En 1995, le DiPel et la formulation bio-encapsulée ont causé une mortalité larvaire significativement plus grande que celle du témoin, au moins 1 jour et jusqu’à 27 jours après les traitements, respectivement. En 1996, bien que 6 mm de pluie soient tombés la journée des traitements, le DiPel et la formulation bio-encapsulée ont causé respectivement 21 et 33 % de mortalité larvaire immédiatement après les traitements. Le DiPel a causé une mortalité significativement plus grande que celle du témoin pour une période de trois jours après les traitements alors que la formulation bio-encapsulée a causé une mortalité plus grande pendant 14 jours. En 1997, deux souches de Btk (HD-1 et BMP123) ont été pulvérisées à des concentrations différentes en matière active (3 et 8 %) et en doses (30 et 240 g 15 L-1). Des concentrations élevées en matière active et des doses élevées ont accru la persistance de l’activité insecticide des formulations de Btk. Parmi les facteurs météorologiques mesurés (précipitations, température et radiations solaires), les précipitations ont réduit la persistance de l’activité insecticide. Les radiations solaires peuvent également avoir contribué à moduler la persistance des formulations.DiPelTM, a registered Bacillus thuringiensis var. kurstaki (Btk)-based formulation, and experimental bio-encapsulated Btk formulations were sprayed in an apple orchard. Their persistence was assessed in the laboratory against obliquebanded leafroller (Choristoneura rosaceana) larvae for three consecutive years. In 1995, DiPel and the bio-encapsulated formulation caused significantly higher larval mortality than the control at least 1 day, and up to 27 days after treatments, respectively. In 1996, although 6.4 mm of rain fell during the day of treatments, DiPel and the bio-encapsulated formulation caused respectively 21 and 33% larval mortality immediately after treatments. DiPel caused significantly higher mortality than the control for up to 3 days while the bio-encapsulated formulation caused significantly higher mortality for up to 14 days. In 1997, two Btk strains (HD-1 and BMP123) were sprayed at different concentrations in a.i. (3 and 8%) and doses (30 and 240 g 15 L-1 applied). Higher concentrations of a.i. in the Btk formulations and higher doses sprayed increased the persistence of the insecticidal activity. Among the meteorological factors that were measured (i.e. precipitations, temperature and solar radiations), precipitations reduced the persistence of the insecticidal activity. Solar radiations may have modulated the persistence of the formulations

MPIFA: A Modified Protocol Independent Fairness Algorithm for Community Wireless Mesh Networks

Community Wireless Mesh Networks (WMN) is a paradigm in wireless communication of 21st centuary as means of providing high speed braodband access. Un-cooperative nodes, both selfish and malicious proves to be a significant threat in Community WMN that require a solution independent of routing protocols being used. We propose to implement Modified PIFA (MPIFA), an Improved version of Protocol Independent Fairness Algorithm (PIFA) proposed by Younghwan Yoo, Sanghyun and P. Agrawal [6] with ability to cater specific requirements in Community WMN. MPIFA has malicious nodes detection rate improvement of 50% when nodes demonstrate low probabilistic malicious behavior of 10% to circumvent the security measures in place. Improvements were also made to reduce false malicious node detections to 4% when node-to-node link failures occur in Community WMN.Comment: Innovative Technologies in Intelligent Systems and Industrial Applications(CITISIA) 200

A multimodal analysis of selected National Lovelife HIV/AIDS prevention campaign texts

Magister Artium - MAThis study investigates the ever-changing trends in visual texts and images used during HIV-prevention campaigns in South Africa. The aim is to evaluate and analyse the effect of multimodal texts used in HIV/AIDS campaigns on the understanding and interpretation by the target group, and thus gauge their effectiveness. Using a text-based multimodal approach (Kress and van Leeuwen, 1996/2006; Martin and Rose, 2004), the study takes into account variables such as socio-economic status, literacy levels, language and cultural differences of readers to evaluate the efficacy of loveLife campaigns to disseminate the HIV/AIDS prevention message. This study focuses on the choice of images and words, and whether they cohere to make a meaningful message. The study analyses how the design features, including images, colour and words, impact on the interpretation of the message and also how the design acts as an aid or barrier to the process of decoding the message. The choice of a two-pronged approach combining multimodality and a text-based (discourse) analyses often favoured by those working in systemic functional linguistics is that it enables the researcher to account for social context, economic, linguistic, cultural and behavioural factors that play a role during the decoding phase.South Afric