Nanolayer CrAlN/TiSiN coating designed for tribological applications

With the goal to produce a hard and tough coating intended for tribological applications, CrAlN/TiSiN nanolayer coating was prepared by alternative deposition of CrAlN and TiSiN layers. In the first part of the article, a detailed study of phase composition, microstructure, and layer structure of CrAlN/TiSiN coating is presented. In the second part, its mechanical properties, fracture and tribological behavior are compared to the nanocomposite TiSiN coating. An industrial magnetron sputtering unit was used for coating deposition. X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used for compositional and microstructural analysis. Mechanical properties and fracture behavior were studied by instrumented indentation and focused ion beam techniques. Tribological properties were evaluated by ball-on-disk test in a linear reciprocal mode. A complex layer structure was found in the nanolayer coating. The TiSiN layers were epitaxially stabilized inside the coating which led to formation of dislocations at interfaces, to introduction of disturbances in the coating growth, and as a result, to development of fine-grained columnar microstructure. Indentation load required for the onset of fracture was twice lower for the nanolayer CrAlN/TiSiN, compared to the nanocomposite TiSiN coating. This agrees very well with their mechanical properties, with H³/E² being twice higher for the TiSiN coating. However, the nanolayer coating experienced less severe damage, which had a strong impact on tribological behavior. A magnitude of order lower wear rate and four times lower steady state friction coefficient were found for the nanolayer coating.     

Thrombotic thrombocytopenic purpura and hemolytic uremic syndrome (TTP/HUS). Description of a series of 35 patients

Subsequent to the implementation of a severity marker stamp in case notes, an audit was performed in 86 admissions with acute asthma to a specialist centre over a 12 month period. Compared to previous audit the documentation of severity markers was significantly better (PEFR: 52% vs 83% p = 0.001, Respiratory rate: 44% vs 81% p = 0.001, ABG: 72% vs 80% p = 0.04, air entry: 58% vs 86% p = 0.001, speech: 27% vs 86% p = 0.001, exhaustion: 4% vs 86% p = 0.001). In contrast to the previous audit where no patient received FiO2 > 0.35, 66% of the cases in the repeat audit received FiO2 0.60 (p = 0.001). The mean duration of admission was five days and showed highest partial correlation (r = 0.6) to the time in hours for the pulse to fall to 80/min. Multiple linear regression showed that this was the only variable best predicting the duration of admission (R2 = 0.3). Admission pulse rate (p = 0.04) and serum K+ (p = 0.04) best discriminated between patients admitted for over and under five days. Logistic regression identified only the admission pulse as significant in calculating the odds of the patient staying in the hospital for > 5 days.     

AI paradigms

The aim of this paper is comparative analysis of most important AI paradigms. An AI paradigm is defined as the pair composed by a concept of intelligence and a methodology in which intelligent computer systems are developed and operated. Three paradigms, the behaviourist paradigm, the agent paradigm, and the artificial life paradigm are discussed.     

Prevention of dark-cutting (DFD) beef in penned bulls at the abattoir

There is a large body of evidence indicating that activities associated with regrouping of bulls before slaughter, which leads to physical exhaustion mainly from mounting, are primary factors inducing dark-cutting (DFD) in beef. The aim of this study was to test several methods to control activity when regrouping cannot be avoided. Fifty bulls previously individually tied for at least 16 months were drafted into groups of five animals and released in a pen at the abattoir. After 18 to 22 h they were slaughtered. According to environmental conditions in the pen, the bulls were divided into four groups: Control group (n = 10, no experimentation); Electricity group (n = 10, an electric fence was constructed above the pen so that a mounting bull would receive an electric shock); Darkness group (n = 10, the whole stall was in darkness); and Combination group (n = 20, both treatments, of the electricity and darkness groups were applied). During the first hour of penning the behaviour of the bulls was videorecorded. After slaughter meat quality characteristics were measured. Dark-cutting was found in Control (70%), Electricity (30%) and Darkness (70%) groups, but not in the Combination group (0%). No treatment altered the repertoire of agonistic activity, but under the combined treatments the number of agonistic interactions was significantly lower than in any other group.     

Corrosion protection of aluminium in acidic chloride solutions with nontoxic inhibitors

Corrosion kinetics of 99.6% aluminium covered by a thin spontaneously formed oxide film in hydrochloric acid solution with and without the presence of substituted N-aryl pyrroles was studied using electrochemical impedance spectroscopy and quasi steady-state polarization. Measurements were performed on a rotating disc electrode in an argon-deaerated solution in the temperature range 20 to 50°C. The addition of inhibitor considerably increases overvoltage of the cathodic process (HER) and shifts Ecorr to negative potential values. The activation energy of the hydrogen evolution reaction was Ea=50±5kJmol–1 and was not affected by the presence of inhibitor. The inhibitory action occurs by -bonding between the adsorbed inhibitor molecules and the electrode surface. The electrode coverage follows the Langmuir adsorption isotherm with an adsorption equilibrium constant K=1.1–2.64×105dm3mol–1. The adsorption of organic compound prevents the adsorption of chloride ions and slow down the rate of corrosion.     

Mass transfer in aerated fermentation broths in a stirred tank reactor

The volumetric mass transfer coefficients, k_La, measured in a pilot plant (0.1 m³) and an industrial (67.5 m³) fermentor during an actual fermentation process are presented. Problems related to the estimation of the phsyical properties as well as to the correlation of experimental data and to scale up procedures are discussed. Although the scale up factor was rather high, both sets of data could be represented by single correlation. Comparison of the experimental data with several available correlations demonstrated the need for pilot plant experiments and scale up procedures, since it is almost impossible to take into account all relevant system properties.     

Formulating the template ILP consistency problem as a constraint satisfaction problem

Inductive Logic Programming (ILP) deals with the problem of finding a hypothesis covering positive examples and excluding negative examples, where both hypotheses and examples are expressed in first-order logic. In this paper we employ constraint satisfaction techniques to model and solve a problem known as template ILP consistency, which assumes that the structure of a hypothesis is known and the task is to find unification of the contained variables. In particular, we present a constraint model with index variables accompanied by a Boolean model to strengthen inference and hence improve efficiency. The efficiency of models is demonstrated experimentally.     

Limitations of a Mapping Algorithm with Fragmentation Mimics (MAFM) when modeling statistical data sources based on measured packet network traffic

Knowing the estimation of a statistical process’s parameters for measured network traffic is very important as it can then be further used for the statistical analyses and modeling of network traffic in simulation tools. It is for this reason that different estimation methods are proposed that allow estimations of the statistical processes of network traffic. One of them is our own histograms comparison (EMHC) based method that can be used to estimate statistical data-length process parameters from measured packet traffic. The main part of EMHC method is Mapping Algorithm with Fragmentation Mimics (MAFM).     

Numerical calculation of digital curve length by using anchored discrete convolution

The paper presents a new method introducing an anchored discrete convolution for calculating the length of a digital curve. The method is based on discrete convolution by using convolution masks and point anchoring in the pixel. The use of ordinary convolution distorts the curve shape and gives large errors in length calculation. The advantage of anchoring is that it limits the point shifting into the pixel during the calculation of the curve length. The method is applied to an analytical arc and various calculations are performed. In addition different methods from the literature were compared and a real sample was tested.