13C NMR study of presence of uron structures in amino adhesives and relation with wood‐based panels performance

The chemical structure of amino adhesives produced by the strongly acid process was investigated by ¹³C Nuclear Magnetic Resonance spectroscopy. This technique allowed the identification of functional groups and its quantitative determination. Concentration of cyclic polymeric structures (urons) was shown to be related with adhesive performance and with particleboard physico‐mechanical properties and formaldehyde content. Higher urons concentration presented lower viscosity and reactivity. Particleboards produced with resins with lower urons concentration presented lower formaldehyde content, but also lower internal bond strength. Wood‐based panels produced fulfilled E1 class requirements for formaldehyde emissions, indicating that strongly acid process is an alternative to the conventional alkaline–acid process. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4500–4507, 2013     

Remaining life assessment of welded pipes containing cracks

The presence of flaws, their size and location in the welded region affects the safe service life of pressure pipes operating at elevated temperature. A remaining life assessment was required to determine the probable remaining safe life of pressure pipes in a high-temperature steam distribution system in which crack-like defects had been identified in many welds. The crack-like defects indicated by NDE lacked the required information to fully identify their locations within the pipe wall. The effect of not knowing complete details of the location of the identified cracks was studied by considering a 360° circumferential crack with initial radial dimension a₀. The crack positions evaluated were: an internal surface crack, an external surface crack, and embedded cracks at various distances from the internal wall of the pipe. Crack growth was modeled using time-dependent fracture mechanics and a newly developed computer code.     

Strategies for revealing deformation and wear mechanisms of polymer composites by combining scanning electron microscopy,energy dispersive x-ray spectroscopy and cross-section techniques—Exemplified by glass fiber reinforced poly-phenylene-sulphide

Polymers and polymer composites are frequently used in tribological applications. However, their use is often limited by excessive wear or plastic deformation, therefore research and development aiming to improve the materials is ongoing. Tribological evaluations of polymer composites often study the friction coefficient and wear rate for different types, sizes and amounts of fillers. But rarely are any mechanisms presented. Although polymer materials differ from metals, the techniques typically used for metal components, for example, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS), can be adapted to polymer materials, to achieve more informative SEM micrographs and EDS analyses. The aim of this article is to present useful analysis strategies, from sample preparation and selection of viewing angles, to selection of instrument settings and detector types. The strategies are exemplified by analysis of poly-phenylene-sulphide filled with glass fiber, evaluated against steel in a reciprocating ball-on-flat test set-up. This article takes its starting point with the worn surfaces, and subsequently analyze them using SEM and EDS. A selection of cross section preparation techniques, analysis parameters and microscopy settings are presented and discussed. By combining these techniques and settings, the observation of a strongly modified surface layer, as well as sub-surface plastic deformation and imbedded wear particles, is facilitated.     

Sensory and chemical evaluation of Thymus zygis L. essential oil and compressed CO2 extracts

The effects of the extraction procedure on the sensory and chemical evaluation of Thymus zygis L. aromatic extracts obtained by hydro distillation and compressed CO₂ extraction were studied. Compressed CO₂ extractions were performed at a temperature of 313 K and 10 and 15 MPa of pressure for 60 min. Aromatic extracts were analysed by GC and GC-MS. Sensorial analysis of the aromatic extracts incorporated into a sunflower oil was carried out by a panel of 20 trained members. The main compounds of Thymus zygis essential oil obtained by Clevenger distillation are: p-cymene (13.6%), thymol (23.8%), geraniol (18.2%), and geranyl acetate (16.3%). The compositions of supercritical extracts are quite different. The detection threshold of Thymus zygis essential oil was 0.001 mg/kg sunflower oil. The preferred level of essential oil incorporation was 0.02 mg/kg sunflower oil (P<0.05). Sensorial attributes were correlated with chemical compositions and it can be concluded that extracts with higher levels of phenols and geranyl acetate were preferred.     

Decrease in cardiovascular disease mortality in the Czech Republic from 1984 to 1993 and its possible causes

BACKGROUND: The objective of the investigation was to evaluate the ten-year development of the cardiovascular mortality rate in two population groups in the age bracket from 25 to 64 years, i.e. in subjects living in six districts which participated in the international WHO project MONICA and in the population of the whole Czech Republic. METHODS AND RESULTS: Data on the mortality rate in 1984-1993 for the age group from 25-64 years were provided by the Institute of Health Information and Statistics, information on the prevalence of risk factors was obtained in three cross-sectional studies implemented in six districts as part of the MONICA project in 1985, 1988 and 1992. In the mortality rate per 100,000 population in the six districts the following changes were revealed (in parentheses the values for 1984 and 1993 are given): men - a statistically significant declining trend in the from all caused mortality (849.3-742.5; p < 0.001) and cardiovascular mortality (367.2-280.4; p < 0.001) and cerebrovascular mortality (69.7-44.8; p < 0.001). In the mortality from ischaemic heart disease (215.7-170.6; ns) a declining trend was not recorded. In women aged 25-64 years in the six districts there was a statistically significant decline of the mortality from all caused (359.5-322.1; p < 0.001), the cardiovascular mortality (115.6-100.6; p < 0.001) and cerebrovascular mortality (31.1-23.6; p < 0.001). The mortality from ischaemic heart disease did not change (49.2-48.8; ns). In the population of the Czech Republic in men the following were detected: a drop of the from all caused mortality (907.1-784.8; P < 0.001), the cardiovascular mortality (383.5-308.4; p < 0.001) and cerebrovascular mortality (76.5-55.3; p < 0.001). Also in women of the Czech Republic a decline of the mortality from all caused was recorded (390.1-328.5; p < 0.001), the cardiovascular mortality (135.3-103.8; p < 0.001), ischaemic heart disease (58.0-48.6; p < 0.001) and cerebrovascular mortality (43.5-27.4; p < 0.001). In 1990 an increased cardiovascular mortality was recorded in men different from the trend during 1984-1993, statistically significant in the Czech Republic (p < 0.05) and in the six districts (p < 0.05). The reasons of this trend are not clear. The role of health services in the mortality drop is not clear, although available data indicate their improvement. Favourable changes were found in risk factors: during the period from 1985-1992 the prevalence of hypercholesterolaemia declined significantly in men and women, the prevalence of hypertension in women and the prevalence of smoking in men declined in the six districts. From nationwide data ensues that after 1989 significant changes occurred in the diet of the Czech population. The meat consumption declined by 1993 by 13%, the milk and dairy product consumption by 26.8% the butter consumption by 43.6% the consumption of vegetable fats increased by 16%, of vegetables by 8%, tropical fruit by 43.2%. These changes probably had an impact on the cholesterol level and BMI of the Czech population. CONCLUSIONS: In the declining cardiovascular mortality trend during 1984-1993 the following may have participated: improved medical care, dietary changes, improvement of the risk profile and other, in particular socioeconomic factors. With regard to the close temporal association of the investigated changes it may be assumed that this development is at least partly associated with changes of the political and economic position in the Czech Republic after 1989.     

Esterification of ethenyl benzene and its derivatives with acetic acid in the presence of perchloric acid as a catalyst

The esterification process of ethenyl benzene and its derivative compounds (p-methyl, p-methoxy, p-chloro, m-methyl, m-nitro and m-chloro, respectively) was carried out with acetic acid and using perchloric acid as a catalyst. From the effects of the variables studied it could be concluded that: the temperature and the catalyst concentration influence positively over the olefin conversion, whereas the initial olefin concentration exert no effect over the same; and that the presence of perchloric salts exerts a different influence, depending on the temperature and on the catalyst concentration. It has been proven that the substituted radicals in the m- or p- positions exert an important influence over the conversion of the studied olefins, presenting growing reactivity in the following order: m-nitro ethenyl benzene, m-chloro ethenyl benzene, p-chloro ethenyl benzene, m-methyl ethenyl benzene, ethenyl benzene, p-methyl ethenyl benzene and p-methoxy ethenyl benzene. Finally, a kinetic and thermodynamic study has been done and the corresponding parameters have been calculated, with an adequate fitting.     

Walter V. Bingham's Library.

Reports on the donation of her husband's library by Millicent Todd Bingham to the Department of Psychology at the University of Oslo, Norway. During the German occupation the library belonging to the Department of Psychology in Oslo was nearly all lost. The Bingham collection (close to 600 volumes plus periodicals) gives a picture of Walter Bingham's wide interests in the field of psychology and its classical works. This generous and invaluable gift will make studies richer and the work more fruitful among Norwegian psychologists both in the present and in generations to come. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An ergonomic study on plate shears, applying physical, physiological and psychophysical methods

An ergonomic evaluation model for hand tools was developed and applied in a project aiming at assessment of work with plate shears. Measurement variables were physical, physiological and psychophysical. They included tool force and opening angle, wrist movements, muscular strain and fatigue, subjective rating of symptoms, and localization of symptoms, in a group of male professional platers. Different hand grips were studied in a series of cutting tasks (4.2 m cutting length). Results showed that working with conventional plate shears is extremely physically demanding. The peak force required was in the range of 26 to 72 per cent of the subjects' maximal hand grip force. There was ample localized muscle fatigue in the forearm. Psychophysical and electrophysiological data agreed with respect to aspects of muscular strain and fatigue. Workers' preferences in the short run seemed to focus on productivity rather than on ergonomic quality. There is a need for development of improved tools, based on formulated requirements.     

Community cardiovascular disease control programmes

A comprehensive approach to the control of cardiovascular diseases on community level is a new venture. There is not yet enough experience in any country with this approach. However, the attempts to develop new approaches are fully justified, since the present stress on hospital care and treatment of the patients has only little changed the incidence of cardiovascular diseases among our populations.     

Conformational changes in the chromatin of tumor cells and the phenomenon of nuclear achromasia

Tumour cell nuclei display achromasia in smears relative to methylene blue and to other low-affinitive ionic dyes. In the course of the smear air-drying the tumour DNA undergoes conformational changes as evidenced by enhanced ethidium and monomer acridine orange uptake and increased sensitivity to DNAse I hydrolysis. Very mild treatment with bleomycin prevents nuclear achromasia with methylene blue in tumour cells. It is concluded that the phenomenon of nuclear achromasia of tumour cells is due to the properties of secondary structure of their DNA.