屋顶与绿化——BTEK科技展览中心

两座连续的金字塔既是BTEK科技展览中心的屋顶,也是该建筑地面以上的所有部分。一个深蓝色的锐角与覆盖草皮的斜坡相映成趣,位于地下的展览中心也制造了与众不同的空间体验。在此案中,屋顶不仅具有独特的形态,也参与空间的塑造和实现绿化的功能。     

High pressure–low temperature processing. Suggested definitions and terminology

Since the first papers reporting the potentials of the pressure-supported freezing and thawing processes for food products appeared, a heterogeneous terminology has been used, due to the novelty of these terms and to the diversity of researchers involved in the new processes, from food technologists and biochemists to engineers and mathematicians. The concepts of high pressure supported, assisted, shift and induced processes have been reviewed and experimental paths have been obtained for different initial pressure–temperature combinations and, after an analytical discussion of the results, a compilation table of terms and paths is proposed. The processes already reported in the literature were reviewed and some other, new processes like pressure-shift thawing, were defined. The text shows the conclusions, in terms of terminology and definitions, of an extended discussion between several universities, research centers and industrial companies, all partners of the European Project QLK1-2002-02230—“Low temperature–pressure processing of foods: Safety and quality aspects, process parameters and consumer acceptance”, SAFE ICE.     

Additive interactions in the stabilization of film grade high-density polyethylene. Part I: Stabilization and influence of zinc stearate during melt processing

The melt stabilization activity of some of the most commercially significant phenolic antioxidants and phosphites (alone and in combination), without and with zinc stearate, was studied in high-density polyethylene (HDPE) produced by Phillips catalyst technology. Multiple pass extrusion experiments were used to degrade the polymer melt progressively. The effect of stabilizers was assessed via melt flow rate (MFR) and yellowness index (YI) measurements conducted as a function of the number of passes. The level of the phenolic antioxidant remaining after each extrusion was determined by high-performance liquid chromatography (HPLC). Phenolic antioxidants and phosphites both improved the melt stability of the polymer in terms of elt viscosity retention; the influence of zinc stearate was found to be almost insignificant. However, phosphites and zinc stearate decreased the discoloration caused by the phenolic antioxidants. A correlation was found between the melt stabilization performance of phosphites and their hydroperoxide decomposition efficiency determind via a model hydroperoxide compound. Steric and electronic effects associated with the phosphorus atom influenced the reactivity towards hydroperoxides. Furthermore, high hydrolytic stability did not automatically result in lower efficiency. Besides phosphite molecular structure, stabilization activity was also influenced by the structure of the primary phenolic antioxidant and the presence of zinc stearate.     

Stem and bunch banana fibers from cultivation wastes: Effect of treatments on physico‐chemical behavior

Much research related to the use of natural fibers in polymeric matrix composites has been developed. The presence of ? OH groups in the chemical components of the natural fibers generates an important hydrophylic tendency that produces adhesion lacks with hydrophobic polymeric matrices. In this work natural fiber bundles mechanically extracted from both stem and bunch of cultivation banana wastes have been modified by both alkalization and silanization treatments. To evaluate the changes introduced by treatments on the chemical structure of fibers, Fourier‐transform infrared spectrophotometry has been employed. The evaluation of advancing dynamic contact angles along with the determination of total surface free energy by using the Owens–Wendt method indicate that the treatments allow reduction of their hydrophilic tendency by alterations on the physicochemical characteristics of the fibers. This behavior is confirmed by the reduction of moisture uptake, analyzed by thermogravimetric analysis. Small differences on noncellulosic components of stem and bunch fiber bundles have been found. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1489–1495, 2004     

Identification of a single nucleotide polymorphism at intron 16 of the caprine acyl-coenzyme A: diacylglycerol acyltransferase 1 (DGAT1) gene

The DGAT1 gene encodes a microsomal enzyme that catalyses the only committed step in triacylglycerol synthesis by joining diacylglycerol and fatty acyl coenzyme A. In cattle, a K232A substitution in the DGAT1 molecule has a significant effect on enzyme activity and milk fat content. The prominent role of this gene in lipid metabolism led us to undertake the structural characterization of DGAT1 in goats. In this way, we have sequenced a 1552 bp fragment of the goat DGAT1 cDNA, which encompasses most of the coding sequence (from exon 1 to 17), and a genomic fragment covering exons 12 to 17. Multiple alignment of the goat DGAT1 sequences revealed the existence of a single nucleotide polymorphism (SNP) involving a T to C substitution at intron 16. We optimized a primer extension based genotyping method that allowed us to determine that the C variant is a minority allele with frequencies ranging from 0.062 (Murciano-Granadina) to 0.109 (Malague?a). This SNP, although not expected to have any functional effect, might be useful as a genetic marker in association studies to detect additional DGAT1 polymorphisms which might influence fat milk content and other traits of economic interest.     

Thermal Microstructural Multiscale Simulation of Solidification and Eutectoid Transformation of Hypereutectic Gray Cast Iron

Although the gray cast iron solidification process has been the subject of several modeling studies, almost all available models appear to deal with only the more widely used hypoeutectic compositions. Models related to hypereutectic gray iron compositions with lamellar (or flake) graphite, and in particular for the proeutectic and eutectoid zones, are hard to find in the open literature. Hence, in the present work, a thermal microstructural multiscale model is proposed to describe the solidification and eutectoid transformation of a slightly hypereutectic composition leading to lamellar graphite gray iron morphology. The main predictions were: (a) temperature evolutions; (b) fractions of graphite, ferrite, and pearlite; (c) density; and (d) size of ferrite, pearlite, and gray eutectic grains; (e) average interlamellar graphite spacing; and (f) its thickness. The predicted cooling curves and fractions for castings with two different compositions and two different pouring temperatures were validated using experimental data. The differences between this model and existing models for hypoeutectic compositions are discussed.     

Robot guided bolt tensioning tool with adaptive process control for the automated assembly of wind turbine rotor blade bearings

The three rotor blade bearings of a wind turbine hub are mounted to the rotor by several hundred bolted joints. Within this assembly process, a specific preload force has to be applied to these bolts in order to achieve a defined clamping force between the bearing and the rotor. Despite high manual labour intensity and safety concerns (platforms need to be raised to reach bolted joint at a height of 4 m), workers use hydraulic bolt tensioning cylinders which need to be threaded on each bolt individually. In order to automate this recurring assembly process, a robot guided bolt tensioning tool has been developed, which is part of a self-adaptive assembly system. Hence, we are able to locate each bolted joint, mount the bolt tensioning tool and apply the preload to each bolt of the bearing sequentially. In order to be flexible for different product variants and compensate the tolerances of large product dimensions in the wind turbine assembly, an adaptive process has been created. Therefore, the relevant parameters describing the product and assembly process are identified which can be adapted depending on the rotor hub type. Furthermore, the tolerance chain is analysed and improved by integrating measurement techniques to the new tool and using these sensors in the adaptive process control.     

Enantioselective Flow Synthesis of a Tetrahydroquinoline SERM Enabled by Immobilized Chiral Phosphoric Acid Catalysis and Diboronic Acid Mediated Selective Nitro Reduction

An asymmetric enantioselective flow process is reported for the formal synthesis of a 1,2,3,4-tetrahydroquinoline selective estrogen receptor modulator. Starting from an easily available 2-nitrochalcone, the first part of the process comprised a telescoped nitro reduction/intramolecular cyclocondensation sequence using diboronic acid as a simple reductant. Subsequent enantioselective transfer hydrogenation in the presence of an immobilized phosphoric acid organocatalyst followed by telescoped N-alkylation furnished the targeted chiral intermediate. The approach ensures flexibility regarding the scale of the synthesis, whilst minimizing the need for intermediate purifications and ensuring environmentally benign metal-free conditions.     

Procedural approach to volumetric terrain generation

The recent outbreak of indie games has popularized volumetric terrains to a new level, although video games have used them for decades. These terrains contain geological data, such as materials or cave systems. To improve the exploration experience and due to the large amount of data needed to construct volumetric terrains, industry uses procedural methods to generate them. However, they use their own methods, which are focused on their specific problem domains, lacking customization features. Besides, the evaluation of the procedural terrain generators remains an open issue in this field since no standard metrics have been established yet. In this paper, we propose a new approach to procedural volumetric terrains. It generates completely customizable volumetric terrains with layered materials and other features (e.g., mineral veins, underground caves, material mixtures and underground material flow). The method allows the designer to specify the characteristics of the terrain using intuitive parameters. Additionally, it uses a specific representation for the terrain based on stacked material structures, reducing memory requirements. To overcome the problem in the evaluation of the generators, we propose a new set of metrics for the generated content.