The influence of catalytic activity on the response of Pt/SnO2 gas sensors to carbon monoxide and hydrogen

The article presents the results of research studies on ceramics SnO₂ sensors with Pt catalysts. The role of catalysis in gas sensing mechanisms was investigated. In order to obtain samples with different catalytic activity but with identical Pt loading, the Pt/SnO₂ catalysts were calcined at different temperatures (400-800 °C). Structural analysis of these samples was performed. Among the sensors manufactured with Pt/SnO₂, the highest sensitivity was shown for the sensor obtained with Pt/SnO₂ sample sintered at 800 °C. The correlation between catalytic activity and sensor sensitivity is given.     

An integrated model for the transshipment yard scheduling problem

A hub-and-spoke railway system is an efficient way of handling freight transport by land. A modern rail–rail train yard consists of huge gantry cranes that move the containers between the trains. In this context, we consider a rail–rail transshipment yard scheduling problem (TYSP) where the containers arrive to the hub and need to be placed on a train that will deliver them to their destination. In the literature, the problem is decomposed hierarchically into five subproblems, which are solved separately. First, the trains have to be grouped into bundles in which they visit the yard. Next, the trains have to be assigned to tracks within these bundles, namely parking positions. Then the final positions for the containers on trains have to be determined. Next, the container moves that need to be performed are assigned to the cranes. Finally, these moves have to be sequenced for each crane for processing. In this paper, an integrated MILP model is proposed, which aims to solve the TYSP as a single optimization problem. The proposed formulation also enables us to define more robust and complex objective functions that include key characteristics from each of the above-mentioned subproblems. The strength of our proposed formulation is demonstrated via computational experiments using the data from the literature. Indeed, the results show that the TYSP can be solved without the use of decomposition techniques and more insight can be obtained from the same input data used to solve particular single decomposed subproblems.     

Optimal design of clamped columns for stability under combined axial compression and torsion

In this paper the problem of the optimal design of columns under combined compression and torsion is investigated. A cross-sectional area varying along the axis of the column which leads to the maximal critical loading is sought. The varying cross-section is approximated either by a function with free parameters or is determined using Pontriagin’s maximum principle.     

Multi-agent system to support decision-making process in design for recycling

In this paper, the application of multi-agent system to support decision-making process in design for recycling is presented. The design for recycling term is highlighted either as the design problem or from the point of view of regulations. The structure of agent system supporting the designer during the design process is showed. The basis of special kind of product model, that is the extension of standard 3D product model, called recycling-oriented product model, is described. The example results of analysis, based on real household appliance model, are presented.     

Meat and fish freshness evaluation by functionalized cantilever-based biosensors

Meat spoilage is a result of an increase in the number of microorganisms and increased levels of biogenic amines (e.g. cadaverine). Destruction of non-spoiled meat products results in substantial waste of resources each year. Currently, the expiration date of meat-products is determined by either subjective sensory and/or expensive and time-consuming microbiological analysis. Cadaverine levels have been demonstrated to be related to the product freshness; however current sensing methods require bulky and expensive chromatography techniques. In this work, the cadaverine binding to a functionalization layer of cyclam (1,4,8,11-tetraazacyclotetradecane) is demonstrated by a systematic study of cyclam/solvent solution influence on morphology and binding. The degradation of the functionalization layer due to storage conditions has also been investigated, and the optimum solvent for the functionalization solution is found to be ethoxyethanol. Functionalized surfaces and cantilevers have been exposed to different types of meat (beef, fish, chicken or pork) and the cadaverine binding has been demonstrated, either by morphology changes (surfaces) or by changes on cantilever resonance frequency due to mass increase (cantilever). The results show a higher cadaverine emission rate for fish, followed by chicken, beef and finally pork.

     

RBF-based neurodynamic nearest neighbor classification in real pattern space

Superposition of radial basis functions centered at given prototype patterns constitutes one of the most suitable energy forms for gradient systems that perform nearest neighbor classification with real-valued static prototypes. It is shown in this paper that a continuous-time dynamical neural network model, employing a radial basis function and a sigmoid multi-layer perceptron sub-networks, is capable of maximizing such an energy form locally, thus performing almost perfectly nearest neighbor classification, when initiated by a distorted pattern. The proposed design scheme allows for explicit representation of prototype patterns as network parameters, as well as augmenting additional or forgetting existing memory patterns. The dynamical classification scheme implemented by the network eliminates all comparisons, which are the vital steps of the conventional nearest neighbor classification process. The performance of the proposed network model is demonstrated on binary and gray-scale image reconstruction applications.     

Asymptotic Preserving scheme for strongly anisotropic parabolic equations for arbitrary anisotropy direction

This paper deals with the numerical study of a strongly anisotropic heat equation. The use of standard schemes in this situation leads to poor results, due to high anisotropy. Furthermore, the recently proposed Asymptotic-Preserving method (Lozinski et al., 2012) allows one to perform simulations regardless of the anisotropy strength but its application is limited to the case where the anisotropy direction is given by a field whose lines are all open. In this paper we introduce a new Asymptotic-Preserving method, which overcomes those limitations without any loss of precision or increase in computational costs. The convergence of the method is shown to be independent of the anisotropy parameter 0<ε<1$0<\epsilon <1$ for fixed coarse Cartesian grids, and for variable anisotropy directions. The context of this work is magnetically confined fusion plasmas.     

Discrete uniform mixtures via posterior means

In this paper, we are concerned with identification of a discrete uniform mixture by the posterior mean. An exact formula for a prior distribution is given. Also some examples featuring negative binomial, negative hypergeometric and beta-Pascal distributions are provided.     

A new cyclometalated rhenium(I) complex

Reaction of Re(CO)₅Cl with 2-phenylbenzothiazole (HΦBT) afforded the cyclometalated Re(CO)₄(ΦBT) complex with the molecular structure of the obtained product confirmed by X-ray investigations. Re(CO)₄(ΦBT) shows intense, hardly dependent on environment, luminescence originating from the π–π* ΦBT intraligand electronic transition. The investigated Re(CO)₄(ΦBT) complex can be considered as a potentially applicable “triplet emitter” for OLED devices.