Oxidation and diffusion study on AlCrVN hard coatings using oxygen isotopes O and O

The present work aims to investigate the oxidation behaviour of AlCrVN hard coatings of equal composition but of different crystal structure. In order to gain more information about the mechanisms that are active during oxidation, a two-stage oxidation procedure has been applied where different isotopes, ¹⁶O and ¹⁸O, were introduced in each step. The analysis by means of secondary ion mass spectrometry depth profiling with its inherent isotope selectivity provided information on the general oxidation behaviour as well as the oxygen diffusion during the oxidation process. The single-phase coating with its face-centred cubic (fcc) structure presents a higher oxidation resistance as compared to the dual-phase coating containing a wurtzite and an fcc phase. After the annealing treatment the surface of the latter is entirely covered by VO₂ and V₂O₅ as evidenced by Raman spectroscopy. The single-phase coating, on the other hand, reveals unoxidised coating material and AlVO₄ crystals. However, even though exhibiting a significantly different oxidation resistance, the oxygen diffusion is similar. In both cases the peak values of ¹⁸O, which was introduced in the second stage, were found near the oxide-nitride interface indicating that O atoms diffused through the already formed oxides. Additional experiments using a gas mixture comprising natural water vapour H₂¹⁶O and ¹⁸O₂ revealed that mainly the presence of molecular oxygen causes oxidation as with increasing water vapour partial pressure the oxide layer thickness was significantly reduced.     

Neutron detection by measuring capture gammas in a calorimetric approach

The neutron capture detector (NCD) is introduced as a novel detection scheme for thermal and epithermal neutrons that could provide large-area neutron counters by using common detector materials and proven technologies. The NCD is based on the fact that neutron captures are usually followed by prompt gamma cascades, where the sum energy of the gammas equals to the total excitation energy of typically 6-9 MeV. This large sum energy is measured in a calorimetric approach and taken as the signature of a neutron capture event. An NCD consists of a neutron converter, comprising of constituents with large elemental neutron capture cross-section like cadmium or gadolinium, which is embedded in common scintillator material. The scintillator must be large and dense enough to absorb with reasonable probability a portion of the sum energy that exceeds the energy of gammas emitted by common (natural, medical, industrial) radiation sources. An energy window, advantageously complemented with a multiplicity filter, then discriminates neutron capture signals against background. The paper presents experimental results obtained at the cold-neutron beam of the BER II research reactor, Helmholtz-Zentrum Berlin, and at other neutron sources with a prototype NCD, consisting of four BGO crystals with embedded cadmium sheets, and with a benchmark configuration consisting of two separate NaI(Tl) detectors. The detector responses are in excellent agreement with predictions of a simulation model developed for optimizing NCD configurations. NCDs could be deployed as neutron detectors in radiation portal monitors (RPMs). Advanced modular scintillation detector systems could even combine neutron and gamma sensitivity with excellent background suppression at minimum overall expense.     

Molecular monitoring of the microbial dynamics occurring on historical limestone buildings during and after the in situ application of different bio-consolidation treatments

Microbially Induced Carbonate Precipitation is proposed as an environmentally friendly method to protect decayed ornamental stone and introduced in the field of preservation of Cultural Heritage. Recent conservation studies performed under laboratory conditions on non-sterile calcarenite stones have successfully reported on the application of a suitable nutritional solution, inoculated and non-inoculated with Myxococcus xanthus, as a bioconsolidation treatment. Furthermore, this procedure has been applied in situ, very recently, to selected historical buildings in Granada, Spain. For the first time, we evaluate the efficiency and risks of the in situ application of the above mentioned treatments onto two historical buildings in Granada. The evaluation consists of a detailed investigation of the micro-biota actively growing during the seven days of the treatments - short-term monitoring and of that remaining on the stones after six and twelve months of the application - long-term monitoring. A molecular strategy, including DNA extraction, PCR amplification of 16S rRNA sequences, construction of clone libraries and fingerprinting by DGGE (Denaturing Gradient Gel Electrophoresis) analysis followed by sequencing was used to gain insight into the microbial diversity present on the differentially treated stones. The monitoring of M. xanthus was performed by PCR using species-specific primers. Similar dynamics were triggered on both buildings by the application of the nutritional solution (inoculated or non-inoculated). 16S rDNA sequencing revealed the dominant occurrence of members belonging to the Firmicutes and Proteobacteria during the seven days of the treatment, whereas after one year the order Bacillales of the phylum Firmicutes was the predominantly detected microorganisms. M. xanthus could be detected only during the seven days of the treatment. The treatments seem to activate no dangerous microorganisms and furthermore, to select the remainder of a homogeneous group of carbonatogenic bacteria on the stones after a long period of time.     

A new system for computer-aided preoperative planning and intraoperative navigation during corrective jaw surgery.

A new system for computer-aided corrective surgery of the jaws has been developed and introduced clinically. It combines three-dimensional (3-D) surgical planning with conventional dental occlusion planning. The developed software allows simulating the surgical correction on virtual 3-D models of the facial skeleton generated from computed tomography (CT) scans. Surgery planning and simulation include dynamic cephalometry, semi-automatic mirroring, interactive cutting of bone and segment repositioning. By coupling the software with a tracking system and with the help of a special registration procedure, we are able to acquire dental occlusion plans from plaster model mounts. Upon completion of the surgical plan, the setup is used to manufacture positioning splints for intraoperative guidance. The system provides further intraoperative assistance with the help of a display showing jaw positions and 3-D positioning guides updated in real time during the surgical procedure. The proposed approach offers the advantages of 3-D visualization and tracking technology without sacrificing long-proven cast-based techniques for dental occlusion evaluation. The system has been applied on one patient. Throughout this procedure, we have experienced improved assessment of pathology, increased precision, and augmented control.     

Flow Cytometry—A New Tool for Direct Control of Fermentation Processes

With flow cytometric cell cycle analysis, fermentation processes become transparent. This implies that we can control the process, by determining growth phases of the yeast population at specific times during the fermentation process, and that the process can be optimised and regulated directly.     

Knowing Activity: Corporate Bridging of Knowledge and Value Creation

We argue that practical endeavours towards mobilising and recreating knowledge is an integral part of value increasing activities, and expose how this dependency can be utilised in ameliorating practice. This bridging of knowledge and value creation constitutes organisational activities as knowing. The paper exposes the efforts of Telenor, a large telecom firm, to create an enduring agenda for non‐financial issues in management. We expose the development process and initial use of their new Integrated Management Business Model. This involves identifying financial and non‐financial drivers of future performance within and across several business units, as well as negotiating on appropriate indicators of both status and change. The paper pays special attention to the iterative approach to development in order to highlight a shift from an attempt to enable knowledge in autonomous processes secluded from everyday activities, towards an understanding of knowledge and knowing as intrinsic to the value creating activities performed. By entering the issue of intangibles through the knowing activity perspective, it was evident that the purpose of the management system was not to determine the status of intangibles in the corporation, it was to improve it.     

Coloring Terms to Control Equational Reasoning

In this article we present an approach to prove the equality between terms in a goal-directed way developed in the field of inductive theorem proving. The two terms to be equated are syntactically split into expressions that are common to both and those that occur only in one term. According to the computed differences we apply appropriate equations to the terms in order to reduce the differences in a goal-directed way. Although this approach was developed for purposes of inductive theorem proving – we use this technique to manipulate the conclusion of an induction step to enable the use of the hypothesis – it is also a powerful method for the control of equational reasoning in general.     

Normovolaemic haemodilution and hyperoxia have no effect on fractal dimension of regional myocardial perfusion in dogs

The neurotoxicity of dibucaine was compared with that of commercially available local anesthetics in studies using rabbit desheathed cervical vagus nerve preparation. Dibucaine dose-dependently suppressed the evoked action potential of myelinated A beta nerve component and nonmyelinated C nerve component. The potential of A beta nerve component was more strongly suppressed, compared with that of C nerve component. At low concentrations of 0.0001-0.001%, the suppression was reversible and recovery with C nerve component was faster and more complete. At higher concentrations, the suppression was irreversible. The minimum concentrations of irreversible blockade were 0.003% for A beta nerve component and 0.03% for C nerve component. Electron microscopically, marked damages in the myelin layer and intraaxonal structure were observed in nerves treated with 0.03% dibucaine. When the neurotoxic effect of dibucaine was compared, in terms of safety margins (minimum concentration of irreversible blockade/clinically used concentrations), with those of commercially available local anesthetics, the rank order was dibucaine, tetracaine and bupivacaine; dibucaine showing the lowest safety margin.