A maximum power tracking algorithm based on photovoltaic current control for matching loads to a photovoltaic generator

In this paper, a novel maximum power point tracking (MPPT) approach is studied. It is based on the photovoltaic (PV) current control. The last one is estimated using an estimation algorithm. It is established based on the Newton Raphson optimization algorithm. Digital simulation results for a resistive load are presented to highlight the improvement in performances of the presented MPPT approach.     

The synthesis and optical properties of novel fluorescent iminocoumarins and bis-iminocoumarins: Investigations in the series of urea derivatives

The condensation of 3-cyano-7-diethylamino-iminocoumarin with various isocyanates and diisocyanates as C-electrophiles gave a new series of N-substituted iminocoumarins and bis-iminocoumarins. The ten compounds obtained were characterized using IR, ¹H NMR, ¹³C NMR, elemental analysis and mass spectrometry. Their optical properties, studied in dichloromethane by UV/vis absorption and fluorescence spectroscopy, were found to depend strongly upon the nature of the substituent borne by the imino group. For the sake of comparison, the optical properties of selected compounds were also analyzed in ethanol. Of the iminocoumarins studied, the alkylurea derivatives displayed the most interesting spectroscopic characteristics and may be of potential use as novel fluorescent probes in media of various polarity.     

Wear behavior of Al–Cu and Al–Cu/SiC components produced by powder metallurgy

In the present study, the dry sliding wear behavior of some powder metallurgy (P/M) Al–Mg–Cu alloys with different weight percentage of Cu (0, 1, 2, 3, 4, and 5 wt%) and corresponding metal matrix composites reinforced with 5 or 10 vol% silicon carbide particles (SiC) have been carried using pin-on-disk apparatus. The tested specimens were tested against hardened steel disk as a counter face at room conditions (∼20 °C and ∼50% relative humidity). The normal load was 40 N and sliding velocity of counter face disk was 150 rpm (0.393 m/s) and total testing time of 60 min, which corresponds to a distance of 1414 m. Generally, both hardness and wear resistance were enhanced by the addition of Cu and/or SiC to the Al-4 wt% Mg alloy. The formations of mechanically mixed layer (MML) as a result of material transfer from counter face disk to the samples and vice versa were observed in all tested specimens.     

Relationship between Riser and Downcomer Gas Holdups in Semi‐batch Circulating Bubble Columns

Gas holdups were measured in a circulating bubble column (CBC) using air‐water system with various additives. The liquid volume in the gas separator affected downcomer gas holdup up to volume ratio equal to 6%. Presence of surface active agents, alcohols, solid particles had little effects on the gas holdups ?_gd — a?_gr relationships. The gas holdups relationships are theoretically related by a single parameter model ?_gd = a?_gr — a + 1, and empirically by two parameter model ?_gd = a?_gr — constant. The theoretical model yielded a values ? 0.45, while the empirical model yielded a values ? 1.16. Analogy between the two models (Contreras et al., 1998) will lead to incorrect conclusions.     

Childhood plaque milia of the inner canthus

BACKGROUND: Milia en plaque is an uncommon skin condition usually seen in adult women, typically in the retroauricular region. We report a new localization in a young child. CASE REPORT: A 6-year-old girl with an uneventful history had developed over the last 7 months an erythematous plaque with numerous whitish-yellow microcysts on the left internal canthus. No local or general favoring factor was found. Skin biopsy showed numerous cystic cavities with an epidermal lining containing layers of keratin within a moderately inflammatory infiltration. The lesion resolved after enucleation of the cysts and no recurrence has been observed after 9 months follow-up. DISCUSSION: Milia en plaque is a charateristic erythematous lesion covered with cysts. The usual localization is the retroauricular region, but other localizations have been reported, mainly on the head. This is the first report involving the internal canthus and also in such a young child. One case of a 15-year-old boy has been discribed. Milia en plaque is often a primary condition as in our case although local or general factors may rarely be inductive. Our case illustrates the different localizations possible for milia en plaque, with predominance on the head, and the possibility of childhood cases. We prefer the term milia en plaque rather than retroauricular milia en plaque.     

Prediction of density,porosity and hardness in aluminum–copper-based composite materials using artificial neural network

The potential of using feed forward backpropagation neural network in prediction of some physical properties and hardness of aluminium–copper/silicon carbide composites synthesized by compocasting method has been studied in the present work. Two input vectors were used in the construction of proposed network; namely weight percentage of the copper and volume fraction of the reinforced particles. Density, porosity and hardness were the three outputs developed from the proposed network. Effects of addition of copper as alloying element and silicon carbide as reinforcement particles to Al–4 wt.% Mg metal matrix have been investigated by using artificial neural networks. The maximum absolute relative error for predicted values does not exceed 5.99%. Therefore, by using ANN outputs, satisfactory results can be estimated rather than measured and hence reduce testing time and cost.     

A new case of false aneurysm of the superior mesenteric artery

The sensitizing capacity of brewer's yeast (Saccharomyces cerevisiae) was studied with the skin prick test method in 449 subjects, including 226 atopic dermatitis (AD) patients, 50 patients with allergic rhinitis (AR) and/or asthma (A), and 173 nonatopic controls. A positive SPT reaction (> or = + +) was seen in 94% of patients with severe AD, in 76% with moderate AD, and in 25% with mild AD or no history of AD. Patients with AR and/or A and nonatopic controls displayed a positive reaction in only 8 and 2% of cases, respectively. There was also a parallel skin prick test reactivity with other yeasts including Pityrosporum ovale and Candida albicans, suggesting cross-reactivity. Parallel skin reactivity was observed also with molds and animal dander but not with pollen or house-dust mite. A significant correlation was also found between total serum IgE level and skin prick test (SPT) results with S. cerevisiae.     

Optimization of <Emphasis Type="Italic">Aspergillus oryzae</Emphasis> S2 α-amylase,ascorbic acid,and glucose oxidase combination for improved French and composite Ukrainian wheat dough properties and bread quality using a mixture design approach

A simplex-centroid experimental design was used for the optimization of both reducing and oxidizing improvers, namely Aspergillus oryzae S2 α-amylase (Amy), ascorbic acid (Asc), and glucose oxidase (GOD). This optimization was performed to enhance the dough and breadmaking qualities of soft French wheat flour and a composite counterpart that contained 30% Ukrainian wheat flour. Statistically significant correlations were calculated between the W index and textural parameters (e.g., dough chewiness and bread cohesiveness). The findings revealed that while the best mixture for French flour comprised 21.8% of Amy, 41.2% of Asc, and 37% of GOD, for the composite counterpart, it comprised 2.3% of Amy, 66% of Asc, and 31.7% of GOD. These optimized mixtures rearranged soft French wheat flour and its composite counterpart to a good quality and an improved flour texture, respectively. Additionally, they increased the loaf specific volumes of the breads made from soft French wheat flour and its counterpart by 25.8 and 45.43%, respectively, significantly decreased the breads’ susceptibility to microbial contamination, and reclassified the breads as “good” in terms of sensory attributes.     

A design for testability approach for nano-CMOS analogue integrated circuits

Dependability requirements must be considered from the beginning when designing safety-critical systems. Therefore, testing should even be considered earlier, intertwined with the design process. The process of designing for better testability is called design for testability (DfT). This article presents two designs for testability and fault diagnosis techniques using a new design analogue checker circuit in order to improve the testability and the diagnosability of nano-CMOS (complementary metal oxide semiconductor) analogue circuits used in safety-critical applications based on the system-on-chip (SoC) approach design. The testing techniques presented in this work can be done during and after the system fabrication. The checker is implemented in full-custom 65 nm Complementary metal–oxide–semiconductor (CMOS) technology with low supply voltage and small-size capabilities. SPICE simulations of the post-layout extracted CMOS checker, which include all parasitic, are used to validate the technique and demonstrate the acceptable electrical behaviour of the checker.     

Elicitation of a reference process model for tool-based micro technologies for planning and controlling purposes and user support

The production of moulded micro components including design, manufacture and quality control is a highly integrated process. A lot of experts, machines, tools, etc. should be deployed meaningfully along this process. The process chain was never written down in detail or as a whole so that new products could be developed on this basis. All developments hitherto have been carried out partly intuitive and partly based on area-specific sub process chains. For an efficient and effective planning and controlling and user support during future tool-based micro product engineering processes, the authors propose a corresponding reference process model. For this purpose, implicit process knowledge must be retrieved from expert’s minds to consider area-specific sub-process chains. For implementation of the reference process model, the Integrated Product Engineering Model (iPeM) will be used.