An open implementation for context-oriented layer composition in ContextJS

Context-oriented programming (COP) provides dedicated support for defining and composing variations to a basic program behavior. A variation, which is defined within a layer, can be de-/activated for the dynamic extent of a code block. While this mechanism allows for control flow-specific scoping, expressing behavior adaptations can demand alternative scopes. For instance, adaptations can depend on dynamic object structure rather than control flow. We present scenarios for behavior adaptation and identify the need for new scoping mechanisms. The increasing number of scoping mechanisms calls for new language abstractions representing them. We suggest to open the implementation of scoping mechanisms so that developers can extend the COP language core according to their specific needs. Our open implementation moves layer composition into objects to be affected and with that closer to the method dispatch to be changed. We discuss the implementation of established COP scoping mechanisms using our approach and present new scoping mechanisms developed for our enhancements to Lively Kernel.     

Spatial frequencies in aesthetic website evaluations--explaining how ultra-rapid evaluations are formed

This study investigates how aesthetic website evaluations, especially those formed after very brief presentations, depend on visual information that is encoded in low- or high-spatial frequencies. A total of 92 participants took part in the experiment. The study used a 3 × 3 mixed design in which presentation time (50, 500 and 10000 ms) and spatial filtering (low-pass filtered, high-pass filtered and unfiltered stimuli) were manipulated. First, we replicate prior results from online studies of high- and low-spatial frequencies. Second, we confirm a prediction from neurocognitive models that only low-spatial frequencies are relevant to aesthetic judgements in ultra-rapid presentation modes. Third, we demonstrate that stimulus repetitions lead to an overestimation of the importance of ultra-rapid stimulus presentations. Taken together, our results highlight the utility of neurocognitive models of visual processing to explain the rapid aesthetic evaluation of websites. PRACTITIONER SUMMARY: Using neurocognitive models we present an approach to explain how aesthetic impressions are formed. We show that ultra-rapid judgements are connected with low- but not with high-spatial frequencies, which are neurologically processed in different visual pathways. Furthermore we identify possible methodological problems in previous studies of ultra-rapid website perception.     

Oxidation protection of carbon-carbon composites by sol-gel ceramic coatings

Carbon-carbon composites were coated with Calcium Magnesium Zirconium Phosphate (CMZP) and Mg-doped Al₂TiO₅ sol-gels in order to form an oxygen barrier at temperatures above 650°C. The coatings were applied using a dipping technique and controlled drying procedures. It was determined that 10 coats of CMZP sol-gel fired every other coat created crack free coatings and oxidation protection. Mg-doped AlTi₂O₅ coatings produced were unsuccessful as oxidation barriers.     

Corrosion properties of titanium based hard coatings on steel

Titanium nitride TiN, titanium boronitride Ti(B,N) and titanium carbonitride Ti(C,N) coatings were deposited by PA-CVD on tempering and stainless steel substrates. The deposition process can be supervised by OES. The coatings were characterized XRD, SEM and WDS as well as hardness, adhesion and friction tests. Electrochemical impedance measurements and cyclic voltammetry in praxis relevant media were carried out. Mechanical and corrosion properties of the coatings can be controlled by the PA-CVD process parameters. The incorporation of chlorine in the coating can be varied by the process parameters with TiCl₄ or completely avoided using metallo-organic precursors. No influence of the chlorine content on the corrosion behavior was observed. Even coatings with extremely high chlorine content still exhibit an excellent corrosion resistance. Thus, the microstructure of the coating is the key to the corrosion properties of hard coatings on steel. A new micro electrochemical scanning droplet technique with a lateral resolution of 150 μm allows the investigation of TiN-coated substrates of complex geometry. The PA-CVD technique permits the deposition of dense and pinhole free coatings. On structures with simulated aspect ratios less than 3, a dense protective coating is proved. However, if the formation of micro pores is not suppressed by the optimal choice of deposition parameters, low-alloyed steel substrates corrode through pores, causing a detachment of the coating. On layers deposited on stainless steel, no sign of substrate corrosion could be detected. A model for the corrosion mechanism is given in Fig. 17.     

Hypertrophied cauda equina presenting as intradural mass: case report and review of literature

BACKGROUND: Hereditary motor and sensory neuropathy types I and III usually lead to enlargement of peripheral nerves. Rarely, spinal nerve roots may also be involved, leading to radiculopathy and/or myelopathy. METHODS: This 44-year-old man with back and lower extremity radicular pain and distal lower extremity weakness and numbness was found to have a nonenhancing intradural mass that caused a nearly complete myelographic block from L1-L4. He underwent a decompressive laminectomy with intradural exploration. RESULTS: Hypertrophic but otherwise normal-looking nerve roots were observed. Subsequent electrodiagnostic testing and sural nerve biopsy confirmed that this patient had a previously unsuspected hereditary motor and sensory neuropathy (HMSN). His pain resolved, but at latest follow-up his weakness and numbness persisted. CONCLUSIONS: Nonenhancing spinal intradural mass lesions may represent enlarged nerve roots, which have a number of potential etiologies. Electrodiagnostic studies and peripheral nerve biopsy are instrumental in establishing the diagnosis of HMSN.     

Aus der Arbeit des Chemikerausschusses der Gesellschaft Deutscher Metallhütten- und Bergleute (GDMB)

Geschichtlicher Rückblick. Gliederung des Ausschusses. Gemeinsame Arbeiten der Chemikerausschüsse GDMB/VDEh. Beispiele aus der praktischen Arbeit. – Bericht anläβlich der 100jährigen Gemeinschaftsarbeit auf dem Gebiet der chemischen Analyse von Eisen und Stahl innerhalb der Stahlindustrie.