Lignin/epoxy composites

This paper presents some possibilities for the use of lignin/epoxy resins in blends and composites with epoxy resins. A compatibility study was carried out by optical and electron microscopy, viscosimetric determinations and thermo-optical analysis in order to establish optimum synthesis conditions of molding mass (cast resins). Lignin/epoxy composites including various fillers (lead soap, alum earth, talc, chalk, sand, trihydrate aluminium oxide, glass fibers), plasticizer (dibutylphthalate and polyester C₆) and pigments (iron-oxide and titanium dioxide) have been obtained. Lignin/epoxy composites are characterized by good dielectric, mechanical and adhesive properties. These composite materials can be used in the electronics industry.     

Analytical formula for three points sinusoidal signals amplitude estimation errors

In this note, we show that the amplitude estimation of sinusoidal signals proposed in Wu and Hong [Wu, S.T., and Hong, J.L. (2010), ‘Five-point Amplitude Estimation of Sinusoidal Signals: With Application to LVDT Signal Conditioning’, IEEE Transactions on Instrumentation and Measurement, 59, 623–630] is a particular case of Vizireanu and Halunga [Vizireanu, D.N, and Halunga, S.V. (2011), ‘Single Sine Wave Parameters Estimation Method Based on Four Equally Spaced Samples’, International Journal of Electronics, 98(7), pp. 941–948]. An analytical formula for amplitude estimation errors as effects of sampling period deviation is obtained.     

Performances of synchronous multiuser detectors for grey-type image transmissions

This article presents the results obtained by three multiuser detectors, namely the conventional, the minimum mean square error and the optimal maximum a posteriori one, when grey images are transmitted, as well as the inter-correlation between users and the amplitude imbalance effects on their performances. Three metrics are used to measure and compare the quality of the received images: the bit error rate, the peak signal-to-noise ratio and the mean structural similarity index. Based on the results obtained, we compared the performances achieved by the three detectors and their sensitivity to system imperfections. Several interesting conclusions are highlighted in the final section.     

Poly(Urethane–Urea) Varnishes Containing Tributyltin Groups

New poly(urethane–urea) varnishes containing tributyltin groups were prepared by the reaction of dibenzyldiisocyanate in excess with a macrodiol (PEGA-2000), trimethylolpropane, diethylene glycol and a bisalcohol maleimide monomer containing tributyltin carboxylate group. Tributyltin maleimide monomers were obtained from 4-{3,4-bis[(2-hydroxyethyl)sulfanyl]-2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl}benzoic acid and bis(tributyltin) oxide. Structure of monomers and polymers was confirmed by the IR, NMR spectroscopy and elemental analysis. The polymer films were characterized by dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), X-ray diffractions, thermogravimetric (TGA) and stress–strain measurements.     

Combined FPPE–PTR Calorimetry Involving TWRC Technique. Theory and Mathematical Simulations

Photopyroelectric calorimetry in the front detection configuration (FPPE) was combined with photothermal radiometry (PTR), in order to investigate dynamic thermal parameters of different layers of a detection cell. The layout of the detection cell consists of three layers: directly irradiated pyroelectric sensor, liquid layer, and solid backing material; and the scanning parameter is the thickness of the liquid layer (thermal-wave resonator cavity method). The theory developed for the two techniques indicates that both FPPE and PTR signals can lead, in the thermally thin regime for the sensor and liquid layer, to the direct measurement of the thermal diffusivity or effusivity of the sensor and/or liquid layer, or the thermal effusivity of the backing material. The two methods offer complementary results and/or reciprocally support each other.     

An empirical model for the melt viscosity of polymer blends

Summary On the basis of experimental data for blends of polyethylene with different polymers an empirical equation is proposed to describe the dependence of melt viscosity of blends on component viscosities and composition. The model ensures the continuity of viscosity vs. composition curves throughout the whole composition range, the possibility of obtaining extremum values higher or lower than the viscosities of components, allows the calculation of flow curves of blends from the flow curves of components and their volume fractions.     

Heterogeneous catalysts obtained by incorporation of polymer-supported phosphonates into silica used in oxidation reactions

Summary The synthesis of copolymers functionalized with phosphonate groups, incorporation of them into ordered meso-macroporous silica, characterization and evaluation of the obtained materials as catalysts in oxidation of cyclohexene are presented. The catalysts obtained are very active and selective in epoxidation of cyclohexene using hydrogen peroxide as an environmentally friendly oxidant.     

Language-dependent recall of autobiographical memories.

Two studies of autobiographical memory explored the hypothesis that memories become more accessible when the linguistic environment at retrieval matches the linguistic environment at encoding. In Experiment 1, Russian-English bilinguals were asked to recall specific life experiences in response to word prompts. The results supported the hypothesis of language-dependent recall: Participants retrieved more experiences from the Russian-speaking period of their lives when interviewed in Russian and more experiences from the English-speaking period of their lives when interviewed in English. In Experiment 2, the language of the interview was varied independently from the language of the word prompts. Both variables were found to influence autobiographical recall. These findings show that language at the time of retrieval, like other forms of context, plays a significant role in determining what will be remembered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comprehensive Review Regarding Mercury Poisoning and Its Complex Involvement in Alzheimer’s Disease

Mercury (Hg) is considered one of the most widespread toxic environmental pollutants, which seems to have multiple effects on organisms even at low concentrations. It has a critical role in many health problems with harmful consequences, with Hg primarily targeting the brain and its components, such as the central nervous system (CNS). Hg exposure was associated with numerous CNS disorders that frequently trigger Alzheimer’s disease (AD). Patients with AD have higher concentrations of Hg in blood and brain tissue. This paper aims to emphasize a correlation between Hg and AD based on the known literature in the occupational field. The outcome shows that all these concerning elements could get attributed to Hg. However, recent studies did not investigate the molecular level of Hg exposure in AD. The present review highlights the interactions between Hg and AD in neuronal degenerations, apoptosis, autophagy, oxidative stress (OS), mitochondrial malfunctions, gastrointestinal (GI) microflora, infertility and altering gene expression.     

Study of the atypical formations in the corrosion bulks of an ancient bronze shield,by optical and electron microscopy

This article presents the atypical formations in the structure of the corrosion crust and in the partially mineralized metallic core, which resulted during the underground stay of a bronze shield, dated between the 1st century B.C. and the 1st century A.D. For our study, we choose a representative fragment from the rim of the shield, which was analyzed by optical microscopy and by electron microscopy coupled with energy‐dispersive X‐ray spectroscopy, to study its morphology, its composition, and the location of chemical compounds on the surface and inside the bulk formed during the underground stay, by processes of chemical and physical alteration, assisted by contamination with structural elements from the site. Those processes, by monolithization and mineralization formed a series of structures consisting of congruent elements and phases with a complex composition. Those formations, defined as surface effects generated by exogenous factors and endogenous factors inside the bulk, are frequently found in ancient bronze objects (such as the exterior flat mole formations and the Liesegang effect in the stratigraphic structure of the bulk). Some of those structures have atypical characteristics as regards their structure, composition, and formation mechanism, which may be used in archeometry. Moreover, that includes the object in the category of special cases, in terms of artifact evolution during underground stay and of the atypical formations resulted from the action of pedological and environmental factors. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.