Relational structures model of concurrency

The paper deals with the foundations of concurrency theory. We show how structurally complex concurrent behaviours can be modelled by relational structures (X, ¨, \sqsubset){(X, \diamondsuit, \sqsubset)} , where X is a set (of event occurrences), and ¨{\diamondsuit} (interpreted as commutativity) and \sqsubset{\sqsubset} (interpreted as weak causality) are binary relations on X. The paper is a continuation of the approach initiated in Gaifman and Pratt (Proceedings of LICS’87, pp 72–85, 1987), Lamport (J ACM 33:313–326, 1986), Abraham et al. (Semantics for concurrency, workshops in computing. Springer, Heidelberg, pp 311–323, 1990) and Janicki and Koutny (Lect Notes Comput Sci 506:59–74, 1991), substantially developed in Janicki and Koutny (Theoretical Computer Science 112:5–52, 1993) and Janicki and Koutny (Acta Informatica 34:367–388, 1997), and recently generalized in Guo and Janicki (Lect Notes Comput Sci 2422:178–191, 2002) and Janicki (Lect Notes Comput Sci 3407:84–98, 2005). For the first time the full model for the most general case is given.     

CMOS current conveyor for ±3 v supply operation

The paper presents a precision CMOS current conveyor (CCII⁺), working in class A, suitable for low supply voltages (±3 V). Owing to a new solution of its input stage, a very lowx-input resistance (about 10 ) has been achieved without applying any loop of negative feedback. Since the circuit includes no high-gain feedback loop, there was no need to use a frequency-compensating capacitor (introducing a dominant pole) in order to ensure its stability. As a consequence, the conveyor is characterized by a higher bandwidth, for a given manufacturing process, compared to circuits including such capacitors. To ensure a high performance under the low supply conditions, a special cascode proposed in [1] has been applied which enables to realize precision current mirrors. PSPICE simulation studies based on detailed level-2 transistor-models are given. The obtained results are in a good agreement with the theory presented and show good properties and potentials of the conveyor.     

Psychosocial aspects of children and families treated with hemodialysis

Introduction: The aim of this study was to analyze the selected psychosocial aspects of chronic kidney disease in children treated with hemodialysis (HD). Methods: The study included 25 children treated with HD aged 2 to 18 years and their parents. Data concerning the illness and socio‐demographic parameters was collected. We used the Paediatric Quality of Life Inventory (PedsQL) for patients and for their parents the PedsQL‐proxy version, General Health Questionnaire (GHQ‐12), Berlin Social Support Scales (BSSS), and the Caregivers Burden Scale (CBS) to evaluate health‐related quality of life (QoL) of HD children and their primary caregivers. Findings: In the PedsQL test, the QoL of HD children was lower than in healthy children. Children treated with HD assessed their QoL on the PedsQL questionnaire higher than the primary caregivers, on all subscales as well as an overall health‐related QoL. Scoring below 2 on the GHQ‐12 test was reported in 56% of mothers, which may indicate that psychological symptoms have intensified. There was no correlation between BSSS, CBS, and GHQ‐12. Discussion: The assessment of QoL in pediatric patients would allow for the earliest possible identification of their nonsomatic problems and irregularities. This could, consequently, contribute to improving QoL in both children with chronic kidney disease and their families.     

Modelling concurrency with comtraces and generalized comtraces

Comtraces (combined traces) are extensions of Mazurkiewicz traces that can model the “not later than” relationship. In this paper, we first introduce the novel notion of generalized comtraces, extensions of comtraces that can additionally model the “non-simultaneously” relationship. Then we study some basic algebraic properties and canonical representations of comtraces and generalized comtraces. Finally we analyze the relationship between generalized comtraces and generalized stratified order structures. The major technical contribution of this paper is a proof showing that generalized comtraces can be represented by generalized stratified order structures.     

Analysis of fluid flow and energy transport in Czochralski's process

In this paper the conjugate fluid flow and energy transport problem (involving conduction-convection-radiation heat transfer) resulting from the Czochralski crystal growth process is analysed. The solidifying material is treated as a pure and semitransparent substance with material properties depending neither on temperature nor on the wavelength. The solution of the problem is obtained iteratively using two computer codes: FLUENT, a commercial CFD package, and BEM-based in-house code capable of analysing the radiative heat transfer in the entire computational domain.Obtained results not only show velocity field and temperature distribution within the bodies under consideration but also demonstrate the influence of thermal radiation on these quantities.     

Surfactant free fractions of metallic and semiconducting single-walled carbon nanotubes via optimised gel chromatography

We report the procedure of sorting/purification of carbon nanotubes by electronic type using chromatographic column with sodium dodecylsulfate (SDS) and sodium deoxycholate (DOC) solutions as the eluents. The non-commercial agarose gel in different concentrations has been tested in the process. It was found that in optimal gel concentration the fractionation resulted in ～96.2% yield of semiconducting species. Importantly, to get surfactant-free fractions the post-separation purification procedure has been carried out. The UV–vis–NIR and Raman spectroscopy have been utilised for the samples analysis. High resolution transmission microscopy and thermogravimetric analysis allowed to study the sample morphology and purity, respectively.