Investigation of the Embedded Element Technique for ModellingWavy CNT Composites

This paper presents a comparison of different finite element approaches to modelling polymers reinforced with wavy, hollow fibres with the aim of predicting the effective elastic stiffness tensors of the composites. The waviness of the tubes is described by sinusoidal models with different amplitude-to-wavelength parameters. These volume elements are discretized by structured volume meshes onto which fibres in the form of independently meshed beam, shell or volume elements are superimposed. An embedded element technique is used to link the two sets of meshes. Reference solutions are obtained from conventional three-dimensional volume models of the same phase arrangements. Periodicity boundary conditions are applied in all cases and fibre volume fractions of up to a few percent are considered. The results indicate that embedded element techniques using shell elements for discretizing the fibres may provide an attractive combination of accuracy, computational cost and flexibility for modelling composites reinforced by arbitrarily, three-dimensionally curved nanotubes.     

Phenomenological modeling of anisotropy induced by evolution of the dislocation structure on the macroscopic and microscopic scale

This work focuses on the modeling of the evolution of anisotropy induced by the development of the dislocation microstructure. A model formulated at the engineering scale in the context of classical metal plasticity and a model formulated in the context of crystal plasticity are presented. Images obtained by transmission-electron microscopy (TEM) show the influence of the strain path on the evolution of anisotropy for the case of two common materials used in sheet metal forming, DC06 and AA6016-T4. Both models are capable of accounting for the transient behavior observed after changes in loading path for fcc and bcc metals. The evolution of the internal variables of the models is correlated with the evolution of the dislocation structure observed by TEM investigations.     

Atomistische Simulation von amorphen TiO2‐Strukturen für optische Schichtsysteme

Atomistic simulations of amorphous titanium dioxide optical thin films The main idea of the present contribution is to give a brief overview of the possible ways to model optical oxide materials, as e.g., amorphous titanium dioxide (TiO₂). At the forefront of current research is an effective approximate density‐functional‐based method (DFTB) that allows one to get a view on the local structure‐property relationships at the atomistic level. Perspective ways of extending the knowledge to other types of materials that require a large‐scale treatment, i.e., to interfaces, will be shown. The reported investigations have been performed within the framework of PLuTO pilot project for the plasmadeposited optical layer systems.     

Physics Performance of the Barrel RPC System of the HARP Experiment

The physics performance of the barrel RPC system of the HARP experiment is described. In the barrel two sets of fifteen identical resistive plate chambers (RPCs) have been operated in 2001 and 2002 as a part of the HARP experiment at the CERN PS accelerator. For the first time under real experimental conditions RPCs have bean applied for particle identification (PID) by measuring the particle's time-of-flight (ToF). The procedure developed for the RPC calibration, based on reconstructed tracks in the HARP Time Projection Chamber (TPC), is described in detail. Intrinsic RPC time resolutions of 141 ps and a combined time resolution of the large angle TOF system of 180 ps are obtained. The effective resolution of the comparison of predicted and measured ToF is 305 ps in the region of interest for this experiment. The PID capabilities of the system are demonstrated. An average efficiency of the RPC counters of about 97% is measured     

High hydrogen content super-lightweight intermetallics from the Li–Mg–Si system

The existence of Li-rich super-lightweight intermetallics in the Li–Mg–Si ternary system has attracted attention for high capacity hydrogen storage materials. The hydrogenation properties of the alloys were studied by thermogravimetric analysis, differential scanning calorimetry in H₂ atmosphere and X-ray diffraction. The Li-rich alloy absorbs the highest amount of hydrogen (8.8% w/w for Li₇₀Mg₁₀Si₂₀), while the Mg-rich alloy (Li₃₀Mg₄₀Si₃₀) absorbs 6.0% w/w H₂ and shows the first experimental evidence for LiMgH₃ formation with LiNbO₃-type structure during hydrogenation.     

Adenosine Kinase Isoforms in the Developing Rat Hippocampus after LiCl/Pilocarpine Status Epilepticus

LiCl/pilocarpine status epilepticus (SE) induced in immature rats leads, after a latent period, to hippocampal hyperexcitability. The excitability may be influenced by adenosine, which exhibits anticonvulsant activity. The concentration of adenosine is regulated by adenosine kinase (ADK) present in two isoforms—ADK-L and ADK-S. The main goal of the study is to elucidate the changes in ADK isoform expression after LiCl/pilocarpine SE and whether potential changes, as well as inhibition of ADK by 5-iodotubercidin (5-ITU), may contribute to changes in hippocampal excitability during brain development. LiCl/pilocarpine SE was elicited in 12-day-old rats. Hippocampal excitability in immature rats was studied by the model of hippocampal afterdischarges (ADs), in which we demonstrated the potential inhibitory effect of 5-ITU. ADs demonstrated significantly decreased hippocampal excitability 3 days after SE induction, whereas significant hyperexcitability after 20 days compared to controls was shown. 5-ITU administration showed its inhibitory effect on the ADs in 32-day-old SE rats compared to SE rats without 5-ITU. Moreover, both ADK isoforms were examined in the immature rat hippocampus. The ADK-L isoform demonstrated significantly decreased expression in 12-day-old SE rats compared to the appropriate naïve rats, whereas increased ADK-S isoform expression was revealed. A decreasing ADK-L/-S ratio showed the declining dominance of ADK-L isoform during early brain development. LiCl/pilocarpine SE increased the excitability of the hippocampus 20 days after SE induction. The ADK inhibitor 5-ITU exhibited anticonvulsant activity at the same age. Age-related differences in hippocampal excitability after SE might correspond to the development of ADK isoform levels in the hippocampus.     

Clinical characteristics, immediate therapeutic results and the outcome in rhythm and conductivity disturbances in myocardial infarct

Certain rhythm and conduction disorders in 252 patients with myocardial infarction were studied. Twenty one of them had auricular fibrillation, influenced by medicaments, with the exception of one, six had relapses and 4 of the patients died. Ventricular extrasystoles (frequent, polytopic, more than three one after the other, R of T) were found in 48 patients. Regardless of the reported good result from the treatment of ventricular extrasystoles, ventricular tachycardia originated in 10 and ventricular fibrillation--in 9 patients. Ventricular fibrillation (a total of 29 patients) was more frequent in patients with cardiac insufficiency (25%) as compared with those (6.1%). With the combination of cardiac insufficiency and ventricular extrasystole, a very high risk group is formed--every third patient develops ventricular fibrillation. Four patient out of 22 patients, were discharged with timely initiated treatment of the ventricular fibrillation. Complete atrioventricular block was recorded in 12 of the patients with a lethality of 50%. Conclusions are drawn as regards the duration of prophylaxis and treatment of rhythm and conduction disorders and in-patient days of the patients in the intensive care unit.