Fast full‐color reflective display via photoluminescent enhancement

Reflective displays are advantageous in applications requiring low power or daylight readability. However, there are no low‐cost reflective technologies capable of displaying bright colors. By employing photoluminescence to more efficiently use ambient light, we created a prototype display that provides bright, full color in a simple, low‐cost architecture. This prototype includes a novel electrokinetic shutter, a layer that incorporates patterned luminescent red, green, and blue sub‐pixel elements, and a novel optical out‐coupling scheme. The luminescent elements convert otherwise‐wasted portions of the incident spectrum to light in the desired color band, resulting in improved color saturation and lightness. This prototype provides a color gamut that is superior to competing reflective display technologies that utilize color filters in single‐layer side‐by‐side sub‐pixel architectures. The current prototype is capable of switching in <0.5 s; future displays based on an alternative electro‐optic shutter technology should achieve video rate operation. A transflective version of this technology has also been prototyped. The transflective version utilizes its backlight with a power efficiency that is at least three times that of a conventional liquid crystal display. These photoluminescence‐based technologies enable a host of applications ranging from low‐power mobile products and retail pricing signage to daylight readable signage for outdoor advertising segments.     

Formation of amorphous Ni-Zr alloy powder by mechanical alloying of intermetallic powder mixtures and mixtures of nickel or zirconium with intermetallics

Mechanical alloying was used to synthesize Ni_xZr_1–x alloys from mixtures of intermetallic compound powders, and also from mixtures of intermetallic compound powders and pure elemental powders. The mechanically alloyed powders were amorphous in the range 0.24 x 0.85. This range is larger than amorphous alloys produced by the melt-spinning technique and mechanical alloying of elemental crystalline powders. Two-phase mixtures of the amorphous phase and the corresponding crystalline terminal solid solution were formed in the range 0.10 x 0.22, and x=0.90. It is found that the morphological development during mechanical alloying of these powders is different from mechanical alloying using only pure ductile crystalline elemental powders. The thermal stability has been investigated. The enthalpy and activation energy of crystallization for Ni-Zr amorphous powders prepared by mechanical alloying are lower than those for melt-spun samples of the same composition. The crystallization temperature of the mechanically alloyed Ni-Zr amorphous powders is higher than that of meltspun samples in the composition range Ni₂₀Zr₈₀ to Ni₃₃Zr₆₇ and Ni₄₀Zr₆₀ to Ni₆₀Zr₄₀. The presence of tiny crystallites as nucleation centres and high oxygen levels in the mechanically alloyed amorphous alloys might be responsible for the differences in crystallization behaviour. A new crystalline metastable phase was observed during crystallization studies of Ni₂₄Zr₇₆ amorphous powder.     

Luminescent Amphiphilic Aminoglycoside Probes to Study Transfection

We report the characterization of amphiphilic aminoglycoside conjugates containing luminophores with aggregation-induced emission properties as transfection reagents. These inherently luminescent transfection vectors are capable of binding plasmid DNA through electrostatic interactions; this binding results in an emission “on” signal due to restriction of intramolecular motion of the luminophore core. The luminescent cationic amphiphiles effectively transferred plasmid DNA into mammalian cells (HeLa, HEK 293T), as proven by expression of a red fluorescent protein marker. The morphologies of the aggregates were investigated by microscopy as well as ζ-potential and dynamic light-scattering measurements. The transfection efficiencies using luminescent cationic amphiphiles were similar to that of the gold-standard transfection reagent Lipofectamine® 2000.     

Über die Herstellung von α-Sulfofettsäureestern

Preparation of Esters of α-Sulfo-Fatty Acids A process for the continuous α-sulfonation of saturated fatty acid esters with SO₃ was worked out and a special bleaching process was developed for these products. The conversion, i. e. the degree of sulfonation is of the order of 95–99%. Solvents, further processing steps or purification operations for the separation of by-products are not required.     

Effect of Granule Size on the Structure of Nanoporous Ceramics Based on Organosilicon Polymer

Porosity in nanoporous ceramics produced by pyrolysis of organosilicon polymer at a temperature of 600°C was investigated using the BET method. Samples were molded from fractionated granules produced by single or double milling in a planetary mill of a polymer previously solidified and heat-treated at 200°C. Specific surface area depending on nanopores sharply decreases after the granules reach a size over 250 m in single milling and over 1000 m in double milling. An explanation for these facts is given in the context of synergism.     

13C n.m.r. study of raw materials for carbon black

¹³C n.m.r. spectroscopy has been applied to investigate a number of coal tar and petroleum-derived carbon black feedstocks. Application of the J-modulated spin echo technique is especially rewarding, as this method renders the quaternary carbons directly detectable. Thus the quality of carbon black feedstocks can additionally be gauged on the basis of the contents of quaternary carbons, which is a direct indication of the carbon yield in the carbon black production process.     

Compatibilization of inorganic particles for polymeric nanocomposites. Optimization of the size and the compatibility of ZnO particles

Summary The synthesis of in-situ hydrophobic functionalized ZnO nanoparticles via an emulsion process is systematically investigated. Different parameters are varied, such as precursor salt concentration and ultrasonification, to optimize the size and the size distribution of the ZnO particles. Particles with a size below 25 nm and surrounded by a hydrophobic polymer shell can be easily obtained. The influence of the polymeric shell on the compatibility with different polymeric matrices is described. Due to the small size of the inorganic particles and the excellent hydrophobization, highly transparent inorganic/organic nanocomposites can be obtained by spin-coating and extrusion.     

Upcycling of polypropylene with various concentrations of peroxydicarbonate and dilauroyl peroxide and two processing steps

The influence of two peroxides (peroxydicarbonate/dilauroyl peroxide) with various concentrations (10–200 mmol/kg PP) and their effective opportunity to introduce long chain branched (LCB) were investigated. The dependence of a single and double extrusion step and the changes of the properties were studied. Experiments were carried out in a single screw extruder at 180°C for the first extrusion step (modification) and at 240°C for the second extrusion step (processing simulation). Melt flow rate and dynamic rheological properties were studied at a measuring temperature of 230°C. For the definitive determination of long chain branched polypropylene (LCB-PP) served the extensional rheology measurements. The mechanical properties were examined via tensile test and impact tensile test. Summarized, LCB (melt strength) could be observed via extensional rheology for all modified specimens and the mechanical properties were maintained or even improved for the modified samples. Particularly, samples containing dilauroyl peroxide display excellent mechanical properties in this study.     

Smoothed Particle Hydrodynamics (SPH) simulation of a high-pressure homogenization process

High-pressure homogenization is a widely used process in the food, pharmaceutical, and cosmetic industry for producing emulsions. Because of small dimensions and high velocities, the experimental and numerical investigation of such a process is challenging. Hence, the development of products is mostly based on trial and error. In this paper, simulations of a generic high-pressure homogenization process using the Lagrangian, mesh-free smoothed particle hydrodynamics (SPH) method are presented and compared to experimental findings using Micro-Particle Image Velocimetry (μ-PIV). The SPH code has been developed and validated with the scope of simulating technical relevant multi-phase problems (Höfler et al. 2012). The present simulations cover the investigation of two different dynamic viscosities of the dispersed phase as well as different droplet trajectories. The comparison between the simulations and the experiments focusses on the velocity distribution of the continuous phase and the droplet deformation and breakup. In both cases a qualitatively good agreement is observed, demonstrating the ability of our SPH implementation for simulating technical relevant two-phase flows.     

The dynamics of avalanches of granular materials from initiation to runout. Part II. Experiments

Summary This paper describes a model to predict the flow of an initially stationary mass of cohesionsless granular material down a rough curved bed and checks it against laboratory experiments that were conducted with two different kinds of granular materials that are released from rest and travel in a chute consisting of a straight inclined section, a curved segment that is followed by a straight horizontal segment. This work is of interest in connection with the motion of landslides, rockfalls and ice and dense flow snow avalanches. Experiments were performed with two different granular materials, nearly spherical glass beads of 3 mm nominal diameter, Vestolen particles (a light plastic material) of lense type shape and 4 mm nominal diameter and 2,5 mm height. Piles of finite masses of these granular materials with various initial shapes and weight were released from rest in a 100 mm wide chute with the mentioned bent profile. The basal surface consisted of smooth PVC, but was in other experiments also coated with drawing paper and with sandpaper. The granular masses under motion were photographed and partly video filmed and thus the geometry of the avalanche was recorded as a function of position and time. For the two granular materials and for the three bed linings the angle of repose and the bed friction angle were determined. The experimental technique with which the laboratory avalanches were run are described in detail as is the reliability of the generated data. We present and use the depth-averaged field equations of balance of mass and linear momentum as presented by Savage and Hutter [28]. These are partial differential equations for the depth averaged streamwise velocity and the distribution of the avalanche depth and involve two phenomenological parameters, the internal angle of friction, ø, and a bed friction angle, , both as constitutive properties of Coulomb-type behaviour. We present the model but do not derive its equations. The numerical integration scheme for these equations is a Lagrangian finite difference scheme used earlier by Savage and Hutter [27],[28]. We present this scheme for completeness but do not discuss its peculiarities. Comparison of the theoretical results with experiments is commenced by discussing the implementation of the initial conditions. Observations indicate that with the onset of the motion a dilatation is involved that should be accomodated for in the definition of the initial conditions. Early studies of the temporal evolution of the trailing and leading edges of the granular avalanche indicate that their computed counterparts react sensitively to variations in the bed friction angle but not to those of the internal angle of friction. Furthermore, a weak velocity dependence of the bed friction angle, , is also scen to have a small, but negligible influence on these variables. We finally compare the experimental results with computational findings for many combinations of the masses of the granular materials and bed linings. It is found that the experimental results and the theoretical predictions agree satisfactorily. They thus validate the simple model equations that were proposed in Savage and Hutter [28].