Thermal Stability of Total Lipids Extracted from Zlatibor Bacon

In this study, non-oxidative and oxidative thermogravimetric analysis was applied as a method for determining the thermal stability of the total lipids extracted from Zlatibor bacon in different phases of production (raw samples, 10th and 30th day of smoking and 30th day of storage). The activation energies of the thermal degradation and oxidation of the total lipids extracted from examined samples were determined. A moderate increase of the activation energy, as well as the other information gained from TG analyses, indicated that there were no significant oxidative changes in Zlatibor bacon lipids during the production and storing.     

Al-Cd Alloy Formation by Aluminum Underpotential Deposition from AlCl3+NaCl Melts on Cadmium Substrate

Aluminum was incorporated into a polycrystalline cadmium electrode surface by underpotential deposition from equimolar AlCl₃+ NaCl melt at 473 K, 523 K, and 573 K (200 °C, 250 °C, and 300 °C). The process was studied by linear sweep voltammetry and potentiostatic deposition/galvanostatic striping. The deposits were characterized X-ray diffraction (XRD), Auger electron spectroscopy (AES), and electron probe microanalyzer (EPMA). The electrochemical measurements showed evidence of Cd-Al alloys being formed but they could not be identified. The growth kinetics of the Cd-Al layers of various proportion and depths that depended on temperature and deposition time were described.     

Distructuring Utopias

In order to meet the challenges of fast-paced urban transformations, Laurent-Paul Robert and Dr Vesna Petresin Robert of Rubedo call for a rethinking of the perennial Utopian model of urban design. They espouse a design strategy that is both able ‘to reflect the dynamics of urban growth and decay’, while meeting the needs of a ‘post-capitalist economy’ - a condition in which change is the only constant. Copyright © 2009 John Wiley & Sons, Ltd.     

An analytical scatter correction for singles-mode transmission data in PET

We present an analytical scatter correction, based upon the Klein-Nishina formula, for singles-mode transmission data in positron emission tomography (PET) and its implementation as part of an iterative image reconstruction algorithm. We compared our analytically-calculated scatter sinogram data with previously validated simulation data for a small animal PET scanner with 68 Ge (a positron emitter) and 57 Co (approximately 122-keV photon emitter) transmission sources using four different phantom configurations (three uniform water cylinders with radii of 25, 30, and 45 mm and a nonuniform phantom consisting of water, Teflon, and air). Our scatter calculation correctly predicts the contribution from single-scattered (one incoherent scatter interaction) photons to the simulated sinogram data and provides good agreement for the percent scatter fraction (SF) per sinogram for all phantoms and both transmission sources. We then applied our scatter correction as part of an iterative reconstruction algorithm for PET transmission data for simulated and experimental data using uniform and nonuniform phantoms. For both simulated and experimental data, the reconstructed linear attenuation coefficients (mu-values-values) agreed with expected values to within 4% when scatter corrections were applied, for both the 68 Ge and 57 Co transmission sources. We also tested our reconstruction and scatter correction procedure for two experimental rodent studies (a mouse and rat). For the rodent studies, we found that the average mu-values for soft-tissue regions of interest agreed with expected values to within 4%. Using a 2.2-GHz processor, each scatter correction iteration required between 6-27 min of CPU time (without any code optimization) depending on the phantom size and source used. This extra calculation time does not seem unreasonable considering that, without scatter corrections, errors in the reconstructed mu-values were between 18%-45% depending on the phantom size and transmission source used.     

An approach in architectural design of energy-efficient timber buildings with a focus on the optimal glazing size in the south-oriented façade

The current research presents an architectural design approach to determine an optimal proportion of the glazing areas in regard to energy-efficiency of prefabricated timber-frame buildings, with a special focus on the south-oriented glazing surfaces. A parametric analysis is performed on the variation of the glazing-to-wall area ratio (AGAW) from 0% to 80% for six different exterior wall elements with different thermal properties. Modifications are performed for the main cardinal directions, while a detailed analysis is carried out only for the south façade. The impact of the presented variable parameters on the energy demand for heating and cooling is analysed with the use of the PHPP software. A basic theoretical contribution of the present research is transformation of a complex energy related problem to only one single independent variable - that of thermal transmittance of the wall elements (U_wall-value), with a view to determining the optimal glazing area size (AGAW_opt) for all contemporary prefabricated timber construction systems. The main aim of the current study is to offer architects a simple and useful shortcut to energy-efficient design of prefabricated timber-frame buildings. The use of mathematical linear interpolation is therefore presented as a simple method for predicting an approximate energy demand with respect to AGAW and U_wall-values.     

A study of pyrolysis of phenolic resin reinforced with carbon fibres and oxidized pan fibres

Pyrolysis of composites prepared from a phenol-formaldehyde resin and carbon fibres (CFRC) or oxidized PAN fibres (OFRC) has been investigated up to 1270 K. Two temperature regions can be distinguished in the pyrolysis of the CFRC: below 770 K the carbon fibres hold the composite structure resisting the tendency of the resin to produce composite shrinkage; above 770 K the CFRC volume and porosity abruptly increase due to a weakening of fibre/resin adhesion. During the pyrolysis of the OFRC a chemical reaction at the fibre/resin interface apparently takes place, beginning at 570 K and producing important changes in the material at 870–970 K. Somewhat smaller weight losses and markedly lesser shrinkage of the pyrolysed composite with respect to its separately treated components have been found. The fibres and the resin coalesce into a product having relatively high density and low porosity, the latter mainly consisting of narrow pores. Hydrogen content of the product is lower than that of the separately treated constituents. The reflections of both the resin and the oxidized PAN fibres are seen only in the X-ray patterns of the OFRC treated at low temperature, but above 670 K only the reflection due to the fibres appears. The interlayer spacing of the fibres in the composite is greater than in the fibres alone treated under the same conditions. According to the IR spectra, the CN groups and aromatic CH groups disappear from the composite at lower temperature than from its components treated separately.The existence of the reaction between the resin and the oxidized PAN fibres, leading to the destruction of the fibre materials, means that the co-carbonization product at 1270 K is not a composite and will not have the necessary mechanical properties. Therefore, this study must continue to look for fibres and matrices which are compatible during co-carbonization to 1270 K.     

Effects of processing on nutritional composition and quality evaluation of candied celeriac

In this work, a new candying procedure with partial re-use of sugar syrup is proposed. Physicochemical analysis, together with sensory evaluation, of candied celeriac samples was done. Candying was performed in a pilot unit at 65‡C, through three cycles of 5 hours duration each. Sugar syrups of 75‡ Brix were used. Effects of 1 % (m/v) citric and 1 % (m/v) ascorbic acid addition, as well as the drying of candied celeriac (60‡C for 8 h) were studied. Sugar syrup deterioration was estimated by the concentration of hydroxymethylfurfural. The results obtained showed that there were no significant(P < 0.01) differences in total dry matter and total sugar content between samples, while the increases after drying were significant(P > 0.01). Differences were observed in sugar compositions between samples. After three cycles, samples turned lighter, with decreasedL* values after drying. The celeriac from the first cycle of the ascorbic acid addition procedure was adjudged best with respect to all quality parameters. The decreased concentration of hydroxymethylfurfural confirmed that re-use of sugar syrup is possible.