InSAR validation based on GNSS measurements in Bucharest

This research aims to complex validate radar displacement products over Bucharest based on Global Navigation Satellite System or GNSS. Validation was represented by the comparison of the recent TerraSAR-X (TSX) displacement results with field GNSS data. For this purpose, 24 and 27 high-resolution images acquired from the TSX satellite between 2011 and 2014 were processed by Permanent Scatterer Inteferometry (PSI) and Small BASeline Subset (SBAS) – interferometric techniques using synthetic aperture radar (SAR) images. The images were selected from a larger pool of SAR images, after consulting weather databases, which helped eliminate the images acquired under adverse weather conditions. GNSS locations were cross-checked on high-resolution optical images and 21 ground points (including three permanent stations) were selected. All these points were (1) characterized by high coherence on radar images; (2) were on the ground; (3) were situated in large vacant spaces; and (4) far away from radar obstacles such as trees. A major challenge in achieving the research goal was to overcome the lack of permanent stations at the ground level within the area of Bucharest. Instead of permanent stations, our team designed and installed forced centring systems that remained stable over time, eliminating the instalment errors of GNSS receivers. The line-of-site (LOS) components derived from GNSS data have been compared with those of the SAR scatterers closest to the GNSS markers (never coinciding). For each location, the vertical reading was projected in the LOS of the SAR sensor. These readings were compared with the displacement values determined at the locations of permanent scatterers (PSs) within 100 m from the GNSS nodes, by eliminating all scatterers on buildings. The comparison has shown a good agreement.     

Real-time worst-case temperature analysis with temperature-dependent parameters

With the evolution of today’s semiconductor technology, chip temperature increases rapidly mainly due to the growth in power density. Therefore, for modern embedded real-time systems it is crucial to estimate maximal temperatures early in the design in order to avoid burnout and to guarantee that the system can meet its real-time constraints. This paper provides answers to a fundamental question: What is the worst-case peak temperature of a real-time embedded system under all feasible scenarios of task arrivals? A novel thermal-aware analytic framework is proposed that combines a general event/resource model based on network and real-time calculus with system thermal equations. This analysis framework has the capability to handle a broad range of uncertainties in terms of task execution times, task invocation periods, jitter in task arrivals, and resource availability. The considered model takes both dynamic and leakage power as well as thermal dependent conductivity into consideration. Thorough simulation experiments validate the theoretical results.     

Chain flexibility versus molecular entanglement response to rubbing deformation in designing poly(oxadiazole-naphthylimide)s as liquid crystal orientation layers

Four poly(oxadiazole-imide)s containing naphthalene rings, with different flexibility and molecular weight, are investigated with respect to their rheological properties to establish the optimal processing conditions from solution phase to film state for liquid crystal orientation purposes. The film uniformity and strength are determined by monitoring the flow behavior and chain entanglements. The solution rheological data are in agreement with film tensile testing, revealing that higher molecular weight favors chain entanglements and implicitly the film mechanical resistance. In order to analyze the suitability of these films as alignment layers their surface is patterned by rubbing with two types of velvet. Liquid crystal alignment of 4′-pentyl-4-biphenylcarbonitrile nematic is tested by polarized light microscopy. The resulting behavior is correlated with the polyimide malleability and characteristics of the textile fibers, namely their polarity, size, and mechanical features. The competitive effects between chain flexibility and entanglements, together with the interactions occurring between the polymer and velvet are analyzed in order to explain the surface regularity, which influences the uniformity of the liquid crystal alignment. The contrast between dark and bright states recorded on the liquid crystal cell indicates that some of these polynaphthalimides are promising candidates for liquid crystal display devices.     

Cleaner production in Romanian textile industry: a case study

This paper reports the changes resulting from adopting environmentally sensitive criteria in Novatextile Pitesti, Romania. The changes have improved the operation of the production plant and reduced costs at the same time.     

pH- and heat-induced structural changes of bovine α-lactalbumin in response to oleic acid binding

Bovine α-lactalbumin (α-LA) is able to interact with fatty acids, resulting in structural changes that are potentially responsible for the HAMLET/BAMLET role. Different states of α-LA induced by pH, temperature and fatty acid binding have been examined. Evidences of the structural changes of α-LA in molten globule and native states in correlation with oleic acid (OA) binding are shown using fluorescence spectroscopy and in silico approach. In addition, the α-LA was subjected to automated docking analysis, to better understand the interaction with oleic acid, using the PatchDock algorithm. The experimental results demonstrate a more flexible conformation of the protein at pH 2.5 when compared to neutral pH, thus facilitating the oleic acid binding to α-LA. The quenching experiments indicate the remarkable increase in the content of molten globule state at pH 2.5 and a more compact and rigid structure for α-LA–OA complexes at pH 7.0. The docking results are consistent with the experimental data concerning the thermal stability of the α-LA–OA complex. α-LA in different conformations/complexes was sensitive to pH and temperature. Several different molecular species induced by pH, heat treatment and oleic acid binding were suggested. The structure of the protein was more flexible at acidic pH, therefore favoring the hydrophobic exposure.     

Wind turbulence used as searching signal for MPPT in variable-speed wind energy conversion systems

The control problem associated to a class of horizontal-axis fixed-pitch variable-speed low-power wind energy conversion systems, working in the partial load region, consisting in the energy conversion maximization, is approached here under the assumption that the wind turbine model and its parameters are poorly known. Using a new approach derived from the optimum seeking methods category, generically called Maximum Power Point Tracking (MPPT), the proposed control solution aims at driving the average position of the operating point near to optimality. Instead of inducing sinusoidal search signals, the wind turbulence is here used as search disturbance. The high-speed shaft's average rotational speed is slowly adjusted using the Fast Fourier Transform processing of some available measures from the system as an estimate of the operating point's position/distance to optimality. Numerical simulations are used for preliminary checking the control law based on this estimation.     

Association of physicochemical with technological properties of wheat

This study focused on twenty‐five different European common wheat varieties and aimed to identify correlations between the most important quality characteristics. When considering the physicochemical characteristics of the wheat samples, our results indicated that milling value is not correlated with vitreous kernel and test weight, but is correlated with gliadin/glutenin. The technological properties of the whole‐wheat flours estimated by means of Mixolab indicated rather good protein quality and the ability to form doughs with good stability in case of most of the samples. Technological behaviour of the flour was affected by dietary fibres and pentosan contents. The starch behaviour was positively correlated with the pentosan contents. The principal components analysis allowed establishing correlations between physicochemical, technological and nutritional parameters of wheat varieties. This finding is important for efficient selecting among wheat varieties, especially when healthy cereal‐based foods are desired.