Recent Developments in Equipment and Application of Ion Beam Assisted Thin Film Deposition

Ion beam assisted deposition (IBAD) of thin films is still a new technology with respect to the number of applications. A broader industrial application depends on the availability and versatility of facilities which are able to process various kinds of workpieces under appropriate conditions. Recently, IBAD facilities of the second generation were described in literature and are partially commercially available. In the present report such IBAD machines with their special features such as number and kind of ion sources and evaporators are described. Particularly, the set-up of the ALLIGATOR, a versatile IBAD device for coating complex workpieces under ion bombardment with a broad range of ion energies, is described. As an application example, recent results on the treatment of medical implants are discussed. In -vivo tests of coated cardiovascular stents showed that the deposited noble metal films were effective in influencing the corrosivity and thromboresistance of the implant     

Single- and multiobjective evolutionary optimization assisted by Gaussian random field metamodels

This paper presents and analyzes in detail an efficient search method based on evolutionary algorithms (EA) assisted by local Gaussian random field metamodels (GRFM). It is created for the use in optimization problems with one (or many) computationally expensive evaluation function(s). The role of GRFM is to predict objective function values for new candidate solutions by exploiting information recorded during previous evaluations. Moreover, GRFM are able to provide estimates of the confidence of their predictions. Predictions and their confidence intervals predicted by GRFM are used by the metamodel assisted EA. It selects the promising members in each generation and carries out exact, costly evaluations only for them. The extensive use of the uncertainty information of predictions for screening the candidate solutions makes it possible to significantly reduce the computational cost of singleand multiobjective EA. This is adequately demonstrated in this paper by means of mathematical test cases and a multipoint airfoil design in aerodynamics.     

The Src family kinase Hck interacts with Bcr-Abl by a kinase-independent mechanism and phosphorylates the Grb2-binding site of Bcr

bcr-abl, the oncogene causing chronic myeloid leukemia, encodes a fusion protein with constitutively active tyrosine kinase and transforming capacity in hematopoietic cells. Various intracellular signaling intermediates become activated and/or associate by/with Bcr-Abl, including the Src family kinase Hck. To elucidate some of the structural requirements and functional consequences of the association of Bcr-Abl with Hck, their interaction was investigated in transiently transfected COS7 cells. Neither the complex formation of Hck kinase with Bcr-Abl nor the activation of Hck by Bcr-Abl was dependent on the Abl kinase activity. Both inactivating point mutations of Hck and dephosphorylation of Hck enhanced its complex formation with Bcr-Abl, indicating that their physical interaction was negatively regulated by Hck (auto)phosphorylation. Finally, experiments with a series of kinase negative Bcr-Abl mutants showed that Hck phosphorylated Bcr-Abl and induced the binding of Grb2 to Tyr177 of Bcr-Abl. Taken together, our results suggest that Bcr-Abl preferentially binds inactive forms of Hck by an Abl kinase-independent mechanism. This physical interaction stimulates the Hck tyrosine kinase, which may then phosphorylate the Grb2-binding site in Bcr-Abl.     

Evolution with heat treatment of crystallinity in carbons

The variation with heat treatment of the dimensions L_a and L_c of the graphite-like crystallites of graphitizable and non-graphitizable carbons is studied. The increases of L_a and L_c with heat treatment temperature (HTT) owing to three processes (crystallite growth in-plane, coalescence of crystallites along the c-axis and coalescence of crystallites along the a-axis) are functionally separated. The evolution with HTT of the number of crystallites (N_cr), the mean volume of the crystallites (v_cr) and the total volume occupied by the crystallites (V_cr) are determined in terms of the changes of L_a, L_c and d₀₀₂. Since among other characteristics the crystallites form the electrical and thermal conducting phase of the carbon, N_cr, v_cr and V_cr are important parameters in many physical properties of these materials. The developed expressions were applied to a non-graphitizable and to a graphitizable carbon.     

Fabrication process for FEP piezoelectrets based on photolithographically structured thermoforming templates

Microsystem Technologies - Piezoelectrets fabricated from fluoroethylenepropylene (FEP)-foils have shown drastic increase of their piezoelectric properties during the last decade. This led to the...     

Model Driven Performance Analysis of Enterprise Information Systems

This paper describes the particular motivation for performance analysis in the domain of Enterprise Information Systems (EISs) and argues that the Model Driven Architecture (MDA) is a suitable framework for integrating formal analysis techniques with engineering methods appropriate to the domain. The MDA permits natural and economical modelling of design and analysis domains and the relationships between them, supporting both manual and automatic analysis. It incorporates the Unified Modelling Language (UML), which is extensively used to capture system designs. We present our general modelling approach and outline its use in relating models of Enterprise Java Bean (EJB) applications, annotated using standard profiles, to analysable formal models.     

Reversible collapse and Mg release of de- and rehydroxylated homoionic cis-vacant montmorillonites

Homoionic Na⁺, Ca²⁺, Sr²⁺, Li⁺, Cu²⁺ and Zn²⁺ samples of the <2 μm fraction of a cis-vacant montmorillonite from Linden (Bavaria) were steam treated at 200°C (≈1.5 MPa), 240°C (≈3.3 MPa) and 300°C (≈8.0 MPa) after dehydroxylation at temperatures up to 630°C. Cation exchange capacity (CEC) measurements, determination of exchangeable cations and X-ray diffraction (XRD), supplemented by thermoanalytical investigations of the evolved water in a thermobalance linked to a mass spectrometer, infrared (IR) and electron spin resonance (ESR) spectroscopy were employed to obtain information about the state of expandability and structural changes of swellable montmorillonite and the sites of interlayer and octahedral cations after heating and rehydroxylation.The XRD pattern of the initial samples showed a well-defined (001) reflection according to the interlayer cation and its hydration state under laboratory atmosphere. After dehydroxylation the pattern exhibited (001) reflections between 9.6 and 9.8 Å, corresponding to a collapsed structure for all samples. The Na⁺-, Ca²⁺- and Sr²⁺-rich montmorillonites regained partial expandability after rehydroxylation at 200°C and full expandability after rehydroxylation at 300°C if the dehydroxylation temperature was less than 630°C. Rehydroxylation at 300°C of the Cu²⁺- and Zn²⁺-rich montmorillonites did not cause reexpansion, whereas the Li⁺-rich samples recovered a partial swellability after rehydroxylation at 240°C and nearly the full swellability after rehydroxylation at 300°C.The Li⁺-, Cu²⁺- and Zn²⁺-rich samples underwent a strong CEC reduction due to migration of the interlayer cations into the 2:1 layer before dehydroxylation started. After rehydroxylation under water steam Cu²⁺- and Zn²⁺-rich samples released 16–30 meq/100 g of Mg²⁺ from the structure, increasing with the steam temperature. Mg²⁺ release was not observed for the Li⁺-rich montmorillonite.     

Impact of adaptive thermal comfort on climatic suitability of natural ventilation in office buildings

In earlier work [1], NIST developed a climate suitability analysis method to evaluate the potential of a given location for direct ventilative cooling and nighttime ventilative cooling. The direct ventilative cooling may be provided by either a natural ventilation system or a fan-powered economizer system. The climate suitability analysis is based on a general single-zone thermal model of a building configured to make optimal use of direct and/or nighttime ventilative cooling. This paper describes a new tool implementing this climate suitability methodology and its capability to consider an adaptive thermal comfort option and presents results from its application to analyze a variety of U.S. climates. The adaptive thermal comfort option has the potential to substantially increase the effectiveness of natural ventilation cooling for many U.S. cities. However, this impact is very dependent on the acceptable humidity range. If a dewpoint limit is used, the increase is significant for a dry climate such as Phoenix but much smaller for humid climates such as Miami. While ASHRAE Standard 55 does not impose a limit on humidity when using the adaptive thermal comfort option, the necessity of limiting humidity for other reasons needs to be considered.