Synthesis and crosslinking properties of phenolphtalein dimethacrylate

Summary By reacting esterification of phenolphtalein with methacrylate chloride, phenolphtalein dimethacrylate was obtained. Based on the results of elemental analysis, FTIR, ¹H-NMR and ¹³C-NMR spectra, the structure of the product was proposed. The dimethacrylate was used as new crosslinker to crosslink poly(methyl methacrylate) (PMMA). The influence of the amount dimethacrylate on the crosslink density and some properties of the crosslinked polymers networks such as swelling, mechanical properties (tensile strength and elongation at break) and thermal stability were examined.     

Towards language-to-language transformation

This paper proposes a simplicity-oriented approach and framework for language-to-language transformation of, in particular, graphical languages. Key to simplicity is the decomposition of the transformation specification into sub-rule systems that separately specify purpose-specific aspects. We illustrate this approach by employing a variation of Plotkin’s Structural Operational Semantics (SOS) for pattern-based transformations of typed graphs in order to address the aspect ‘computation’ in a graph rewriting fashion. Key to our approach are two generalizations of Plotkin’s structural rules: the use of graph patterns as the matching concept in the rules, and the introduction of node and edge types. Types do not only allow one to easily distinguish between different kinds of dependencies, like control, data, and priority, but may also be used to define a hierarchical layering structure. The resulting Type-based Structural Operational Semantics (TSOS) supports a well-structured and intuitive specification and realization of semantically involved language-to-language transformations adequate for the generation of purpose-specific views or input formats for certain tools, like, e.g., model checkers. A comparison with the general-purpose transformation frameworks ATL and Groove, illustrates along the educational setting of our graphical WebStory language that TSOS provides quite a flexible format for the definition of a family of purpose-specific transformation languages that are easy to use and come with clear guarantees.

     

Properties of diagnostic data distributions

In applications of statistical methods to medical diagnosis, information on patients' diseases and symptoms is collected and the resulting data-base is used to diagnose new patients. The data-structure is complicated by a number of factors, two of which are examined here: selection bias and unstable population. Under reasonable conditions, no correction for selection bias is required when assessing probabilities for diseases based on symptom information, and it is suggested that these "diagnostic distributions" should form the principal object of study. Transformation of these distributions under changing population structure is considered and shown to take on a simple form in many situations. It is argued that the prevailing paradigm of diagnostic statistics, which concentrates on incidence of symptoms for given disease, is largely inappropriate and should be replaced by an emphasis on diagnostic distributions. The generalized logistic model is seen to fit naturally into the new framework.     

Neutron poison distribution in the central reflector to reduce the DLOFC temperature of a Th-LEU fueled OTTO PBMR DPP-400 core

In a previous study using a mixture of thorium and 20 a/o% LEU at 16 gram per fuel sphere heavy metal loading and adjusting the effective fuel enrichment to produce the same amount of cumulative energy per fuel sphere as with the 10 a/o% Low Enriched Uranium (LEU), the maximum Depressurized Loss Of Forced Cooling (DLOFC) temperature was reduced from 2273 to 1925 °C and 1811 °C for a symmetric and asymmetric core, respectively using an once-through-then-out (OTTO) fuelling scheme. This article presents an additional strategy for reducing the maximum DLOFC temperature by placing an optimized distribution of neutron poisons in the central reflector. This strategy produced maximum DLOFC temperatures of 1509 and 1448 °C for the symmetric and the asymmetric cores, respectively. These results are impressive as it means that the less complicated OTTO cycle with its lower capital cost achieved the same cumulative energy produced per fuel sphere than the standard six-pass refuelling scheme and that at substantially lower maximum DLOFC temperatures. Both the addition of the neutron poisons to the central reflector and the creation of a radially asymmetric core resulted in lower burn-ups that had to be reversed by increasing the enrichment of the fuel.     

Phytic acid concentration in selected raw materials and analysis of its hydrolysis rate with the use of microbial phytases during the mashing process

Phytic acid present in the raw materials can complex with many compounds and therefore limit their availability to the yeast during the alcoholic fermentation process. An effective utilization of biogenic compounds bound in phytates requires a detailed analysis of the raw materials for their phytic acid content. The aim of this study was to characterize the major technological parameters for selected raw materials used in the distilling industry (maize, rye, wheat and triticale grain) and to determine the phytic acid content and the IP6/total phosphorus ratio. The phytic acid hydrolysis rate during the mashing process, with the use of microbial phytases, was analysed. The highest phytic acid concentrations (2.30 ± 0.20 mg/g dry matter) and the highest IP6/total P (80.42 ± 6.99%) were observed in the maize grain samples. Therefore, further studies on the phytic acid hydrolysis rate with the use of various phytases were conducted for the maize grain. The highest hydrolytic activity was observed for the Phytase 10000L preparation. This was the preparation that hydrolysed the phytic acid completely in up to 90 min. The application of a highly effective phytase, in ethanol production from maize grain, could lead to a more effective utilization of the biogenic compounds during the fermentation process. Copyright © 2015 The Institute of Brewing & Distilling     

N,N,N-trimethyl chitosan as an efficient antibacterial agent for polypropylene and polylactide nonwovens

The paper presents a method of depositing N,N,N-trimethyl chitosan (TMC) layers onto polypropylene and polylactide nonwovens. A two-step modification procedure is applied: first, grafting the nonwovens with acrylic acid and next layer-by-layer deposition. Turbidimetric measurements confirm the creation of polycomplexes between grafted poly(acrylic acid) and deposited TMC. The created material structure is evaluated using gravimetric analysis, reflectance Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy measurements and pH-metric titration. The modified material exhibits good antibacterial properties against Gram-positive bacteria Staphylococcus aureus.     

Durability and surface chemistry of horizontally aligned CNT films as electrodes upon electrolysis of acidic aqueous solution

We devised a simple and effective method of electrochemical functionalization of horizontally aligned CNT films in diluted HCl and H₂SO₄ solutions upon their electrolysis under a constant current mode. We were able to cause notable generation of carbon–oxygen and carbon–chlorine functional groups on the CNT film anodes as proven by EDX, XPS, and Raman spectroscopy. As a consequence, we observed significant changes of the morphology of the material under electron microscopy, what translated into improved compatibility of CNTs with hydrophilic media. In turn, application of CNT films as cathodes was found as a powerful tool for a thorough cleaning of the nanotubes. Finally, we demonstrated that by the selection of appropriate conditions, CNT films can act as easy-to-make and flexible electrodes with a high stability and performance superior to graphite for generation of non-oxidizing gases such as hydrogen from solution. CNT film electrodes are two orders of magnitude lighter and require much lower overpotential for faradaic splitting of water.     

Formulation and technology research of new silver solder with flux covering

In their eutectic compositions, Au–Si alloys have a melting point of 369°C, and a colour similar to that of high-grade gold. Results of the manufacture of gold alloys with 2.5%, 2.8% and 3.0% silicon, by means of melting in a plasma furnace with an inert argon atmosphere, are presented in this study. Chemical composition characterisation was carried out by energy dispersion spectroscopy and wave dispersion spectrometry, and metallographic and microstructural analysis by optical microscopy, SEM and DRX, Vickers hardness and mircohardness testing, melting point evaluation by DSC and determination of the SCIELab colorimetric coordinates. The results of the hardness and micro-hardness testing gave values around 110HV, presenting an important increase in the mechanical properties with respect to the traditional high purity gold alloys. The melting temperature for the alloys was around 374°C as well as being a heat very close to the values of pure gold.     

Investigation of Serine‐Proteinase‐Catalyzed Peptide Splicing in Analogues of Sunflower Trypsin Inhibitor 1 (SFTI‐1)

Serine‐proteinase‐catalyzed peptide splicing was demonstrated in analogues of the trypsin inhibitor SFTI‐1: both single peptides and two‐peptide chains (C‐ and N‐terminal peptide chains linked by a disulfide bridge). In the second series, peptide splicing with catalytic amount of proteinase was observed only when formation of acyl–enzyme intermediate was preceded by hydrolysis of the substrate Lys–Ser peptide bond. Here we demonstrate that with an equimolar amount of the proteinase, splicing occurs in all the two‐peptide‐chain analogues. This conclusion was supported by high resolution crystal structures of selected analogues in complex with trypsin. We showed that the process followed a direct transpeptidation mechanism. Thus, the acyl–enzyme intermediate was formed and was immediately used for a new peptide bond formation; products associated with the hydrolysis of the acyl–enzyme were not observed. The peptide splicing was sequence‐ not structure‐specific.