The influence of the die and floating plug geometry on the drawing process of tubing

Nowadays, the development of tube drawing process with a floating plug technique has moved our limit up to the production of thick-walled tubes; production of which still belongs to marginal techniques which are different from drawing of standard tubes. The submitted paper is basically a survey of research in fundamental characteristics of tube drawing with a floating plug with the aim to summarize some important results from the theory, which have not yet been published in any English publication. The purpose of this survey is to fill the gap in English literature to promote transfer and exploitation of knowledge. Research in fundamental characteristics was further developed and conditions under which it is possible to draw thick-walled tubes are defined. Confirmed possibility of thick-walled tubes drawing with support provided by a floating plug having negative overlap is the result of theoretical study and practical verification, which enables further moving of drawing process limit.     

Multiple stacked SB-based heterostructures

The subject invention comprises a plurality of serially connected small volume photovoltaic devices. A single device includes a first layer of n+ doped InSb, a second layer of doped IDAs1-xSbx and a third layer of p+ doped InSb. From 2-50 of these devices are grown by either a low-pressure MOCVD or MBE process to a maximum thickness of about 10 mum. Alternatively, the first layer may be n+ doped InyGal-y, Sb the second layer p+ doped InAsl-xSbx and the third layer InyGal-ySb, repeated to a maximum thickness of 10 m.     

Microstructure,Phase Occurrence,and Corrosion Behavior of As-Solidified and As-Annealed Al-Pd Alloys

In the present work, we studied the microstructure, phase constitution, and corrosion performance of Al₈₈Pd₁₂, Al₇₇Pd₂₃, Al₇₂Pd₂₈, and Al₆₇Pd₃₃ alloys (metal concentrations are given in at.%). The alloys were prepared by repeated arc melting of Al and Pd granules in argon atmosphere. The as-solidified samples were further annealed at 700 °C for 500 h. The microstructure and phase constitution of the as-solidified and as-annealed alloys were studied by scanning electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray diffraction. The alloys were found to consist of (Al), ε _n (~ Al₃Pd), and δ (Al₃Pd₂) in various fractions. The corrosion testing of the alloys was performed in aqueous NaCl (0.6 M) using a standard 3-electrode cell monitored by potentiostat. The corrosion current densities and corrosion potentials were determined by Tafel extrapolation. The corrosion potentials of the alloys were found between ? 763 and ? 841 mV versus Ag/AgCl. An active alloy dissolution has been observed, and it has been found that (Al) was excavated, whereas Al in ε _n was de-alloyed. The effects of bulk chemical composition, phase occurrence and microstructure on the corrosion behavior are evaluated. The local nobilities of ε _n and δ are discussed. Finally, the conclusions about the alloy’s corrosion resistance in saline solutions are provided.     

Progress on large area n‐type silicon solar cells with front laser doping and a rear emitter

We report on the progress of imec's n‐type passivated emitter, rear totally diffused rear junction silicon solar cells. Selective laser doping has been introduced in the flow, allowing the implementation of a shallow diffused front surface field and a reduction of the recombination current in the contact area. Simplifications have been implemented towards a more industrial annealing sequence, by replacing expensive forming gas annealing steps with a belt furnace annealing. By applying these improvements, together with an advanced texturing process and emitter passivation by atomic layer deposition of Al₂O₃, 22.5% efficient cells (three busbars) have been realized on commercial 156 · 156 mm² Czochralski‐Si. This result has been independently confirmed by ISE CalLab. Copyright © 2016 John Wiley & Sons, Ltd.     

Rate-distortion driven decoder-side bitplane mode decision for distributed video coding

Distributed video coding (DVC) features simple encoders but complex decoders, which lies in contrast to conventional video compression solutions such as H.264/AVC. This shift in complexity is realized by performing motion estimation at the decoder side instead of at the encoder, which brings a number of problems that need to be dealt with. One of these problems is that, while employing different coding modes yields significant coding gains in classical video compression systems, it is still difficult to fully exploit this in DVC without increasing the complexity at the encoder side. Therefore, in this paper, instead of using an encoder-side approach, techniques for decoder-side mode decision are proposed. A rate-distortion model is derived that takes into account the position of the side information in the quantization bin. This model is then used to perform mode decision at the coefficient level and bitplane level. Average rate gains of 13–28% over the state-of-the-art DISCOVER codec are reported, for a GOP of size four, for several test sequences.     

Effect of seed treatments on the chemical composition and properties of two amaranth species: starch and protein

The seeds of two Amaranth species were studied. The starch contents were 543 and 623 g kg^?1 while crude protein contents were 154 and 169 g kg^?1 for Amaranthus caudatus and Amaranthus cruentus seeds, respectively. The effect of several treatments, including cooking, popping and germination and flour air classification on the protein and starch properties were studied. Air classification decreased the starch content and increased the protein content, while heating increased the protein but did not affect the starch content. Germination decreased both starch and protein contents. Amylose content was increased by air classification and heating, but was not affected by germination. It was found that all treatments increased the starch swelling power and reduced the falling number. The resistant starch content was increased in the high protein flour (HPF) fraction and germinated flour compared with the raw flour, while its content decreased in the heat treated seed flours. These processes also affected the starch gelatinization temperature and peak viscosity. The thermal properties of the starch flour were not affected by air classification while gelatinization energy was decreased significantly (by 52.0 and 90.0% and by 70.0 and 95.0%) in cooked and popped A caudatus and A cruentus seed flours, respectively. The gelatinization energy was highest in germinated seeds dried at 90 °C with values of 2.67 and 3.87 J g^?1. Air classification reduced the level of all protein fractions. Thermal treatment decreased the water‐soluble fraction (albumins + globulins) and alcohol‐soluble fraction (prolamins) in both species. The levels of all fractions except the water‐soluble fraction (albumins + globulins) were reduced significantly in both species by germination, which mainly increased the amount of aspartic acid, serine and alanine, while the amounts of threonine, arginine and tyrosine decreased in both species. The polypeptide bands of the HPF in both species were unchanged compared with the raw seed flours, but more intensive coloured bands were observed. Thermal treatments eliminated major and minor bands above 35.0 KDa in both species. Copyright © 2004 Society of Chemical Industry     

Antioxidant activity screening of extracts from Sideritis species (Labiatae) grown in Bulgaria

Plant samples from several species and populations of the genus Sideritis (Labiatae) grown in Bulgaria (S scardica, S syriaca and S montana) were extracted with different solvents. Their antioxidant activities were determined by the β‐carotene bleaching test (BCBT), 2,2′‐diphenyl‐1‐picrylhydrazyl (DPPH^?) radical scavenging method and static headspace gas chromatography (HS‐GC) and compared with the antioxidant activity of two reference compounds of different polarity, viz butylated hydroxytoluene (BHT) and rosmarinic acid. The pure reference compounds were applied in a ten‐times lower concentration than the plant extracts. The highest antioxidant activity in the BCBT, close to that of BHT, was observed for the more apolar extracts. The inhibitory effect on β‐carotene bleaching of the polar extracts and rosmarinic acid was much lower than that of BHT. The inhibition of hexanal formation in bulk safflower oil by most of S syriaca and S scardica extracts was as effective as BHT but less so than rosmarinic acid. S montana extracts showed weak antioxidant or even pro‐oxidant properties. Extracts from butanol and from ethyl acetate and the total methanol extracts from all Sideritis plants studied showed a strong radical scavenging activity against DPPH^?, close to that of rosmarinic acid. S montana extracts were, as a whole, slightly weaker radical inhibitors than the extracts from the other two species. The antioxidant activity of Sideritis extracts was attributed to the presence of flavonoid and phenylpropanoid glycosides. Copyright © 2003 Society of Chemical Industry     

Actual versus apparent within cell wall variability of nanoindentation results from wood cell walls related to cellulose microfibril angle

Hardness and elastic modulus of spruce wood cell walls parallel to their axial direction were investigated by means of nanoindentation. In the secondary cell wall layer S2 of individual earlywood and compression wood tracheids, a systematic pattern variability was found. Several factors potentially affecting nanoindentation results were investigated, i.e. specimen orientation related to the indenter tip, cutting direction during specimen preparation, tip geometry, specimen and fibre inclination, respectively, and finally micro fibril orientation. Mechanical property measurements were correlated with structural features measured by confocal Raman spectroscopy. It was demonstrated that very high variability in the measurement of micromechanical cell wall properties can be caused by unintentional small fibre misalignment by few degrees with regard to the indentation direction caused by sub-optimal specimen preparation.     

Accumulation of metals and selected nutritional parameters in the field-grown chamomile anthodia

Accumulation of metals and selected nutritional parameters of chamomile (Matricaria chamomilla) anthodia cultured under natural condition on an experimental field in Košice (Slovak Republic) were studied. Two official cultivars (diploid ‘Novbona’ and tetraploid ‘Lutea’) and two ontogenetic phases of anthodia (‘bud’ and ‘flower’) were compared. K, Ca, Mg, Al, Cu, Cr, Hg and Cd were more accumulated in both bud and flower of diploid plants while accumulation of Fe, Zn, Ni and Pb was ploidy-independent. Bioaccumulation factor was lower than one for toxic metals, indicating that chamomile is an excluder. Tetraploid plants contained lower concentrations of amino acids but higher concentrations of phenolic acids compared to diploid plants. Among phenolic acids, caffeic and vanillic acids were mainly present in the glycosidic form. Reducing sugars (glucose equivalents), total soluble phenols, sum of flavonols, individual flavonols (quercetin and kaempferol), apigenin and herniarin were more accumulated in anthodia of tetraploid plants. Our data indicate that increase in ploidy level reduces accumulation of toxic metals and amino acids but enhances accumulation of phenolic metabolites. Thus polyploidisation is a good tool to achieve safer chamomile cultivars for pharmaceutical purposes.