Temperature and pump power dependent photoluminescence characterization of MBE grown GaAsBi on GaAs

Bulk and quantum well GaAs_1?xBi_x/GaAs layers with Bi mole fractions from 0.02 to 0.10 are grown by molecular-beam epitaxy at temperatures ranging from 280 to 320?°C. The samples are characterized using temperature and pump-power dependent photoluminescence measurements covering 8–300?K and 1–250?mW (7–1,800?W/cm²), respectively. The results indicate that there is strong reduction in bandgap energy with the incorporation of small amounts of Bi and that GaAsBi most likely forms a weak type-I band alignment with GaAs.     

Increase in Generation of Poly-Crystalline Silicon by Atmospheric Pressure Plasma-Assisted Excimer Laser Annealing

In this work, a novel atmospheric pressure plasma-assisted excimer laser annealing method for increasing the generation efficiency of poly-crystalline silicon from amorphous silicon layers is presented. Here, both the plasma and the laser propagate coaxially in order to generate energetic synergies. The influence of different process gases and plasma discharge modes as well as the working distance were investigated. Depending on the particularly applied plasma, the crystalline area was increased by a factor of approx. 1.1 to 1.9, where the highest efficiency was observed when introducing an argon plasma beam to the annealing process.     

Finite element study of the effect of material properties on reaction forces produced by solitary wave propagation in granular chains

The response of a granular chain to impulse loading was investigated as a function of material properties. Using COMSOL Multiphysics, the elastic modulus and density of the grains were varied while the piston and force sensor properties remained fixed. The result of solitary wave propagation through the granular chain was recorded at the force sensor as a series of reaction force waves. It was found that wave velocity and amplitude increased with elastic modulus. Increasing density caused a decrease in wave velocity and an increase in amplitude. In addition, higher density granular chains exhibited a decrease in the number of waves in their respective reaction force wave trains. LS-DYNA was then used to explore the response of a variety of ceramic and metallic granular chains. Density, elastic modulus, and Poisson’s ratio were all set to representative values for the respective material. It was found that solitary wave development and decay occurred at different rates for different materials. In addition, the kinetic energy decay of the impactor was slower for glass compared with tungsten. Finally, it was shown that a single reaction force wave with no train could be produced by impacting a high density, high modulus chain such as tungsten with a glass piston, which has relatively low density and elastic modulus. Increasing impact velocity for this case resulted in a single high-amplitude wave with no train.     

One‐Step Formulation of Protein Microparticles with Tailored Properties: Hard Templating at Soft Conditions

Formulation of therapeutic proteins into particulate forms is a main strategy for site‐specific and prolonged protein delivery as well as for protection against degradation. Precise control over protein particle size, dispersity, purity, as well as mild preparation conditions and minimal processing steps are highly desirable. It is, however, hard to fit all these criteria with conventional preparation techniques. Here a one‐step hard‐templating synthesis of microparticles composed of functional, non‐denatured protein is reported. The method is based on filling porous CaCO₃ microtemplates with the protein near to its isoelectric point (pI) followed by pH‐ or EDTA‐mediated dissolution of the tempplates. In principle, a wide variety of proteins can be converted into microparticles using this approach. The main requirement is an overlap of the protein insolubility and a template solubility for a certain parameter (here pH or EDTA). Here the formulation of insulin particles is studied in detail and it is shown that particles consisting of high molecular weight protein (catalase) can also be prepared. In this context, the synthesis of CaCO₃ templates with controlled size, the mechanism of the protein microparticle formation and mechanical properties of the microparticles are discussed. For the first time, the fabrication of mesoporous monodispersed CaCO₃ microtemplates with identical porocity but tuned diameter from 3 to 20 μm is demonstrated. The protein particle diameter can be adjusted by choosing the appropriate template size that is critical for successful pulmonary delivery of insulin. As a first step towards insulin delivery, the in vitro release of insulin at physiological conditions is studied.     

Cargo scheduling decision support for offshore oil and gas production: a case study

Woodside Energy Ltd (Woodside), Australia’s largest independent oil and gas company, operates multiple oil and gas facilities off the coast of Western Australia. These facilities require regular cargo shipments from supply vessels based in Karratha, Western Australia. In this paper, we describe a decision support model for scheduling the cargo shipments to minimize travel cost and trip duration, subject to various operational restrictions including vessel capacities, cargo demands at the facilities, time windows at the facilities, and base opening times. The model is a type of non-standard vehicle routing problem involving multiple supply vessels—a primary supply vessel that visits every facility during a round trip taking at most 1 week, and other supply vessels that are used on an ad hoc basis when the primary vessel cannot meet all cargo demands. We validate the model via test simulations using real data provided by Woodside.