One-dimensional model of solar thermal reactors for the co-production of hydrogen and carbon black from methane decomposition

The solar thermal decomposition of methane is a promising route for the large scale production of hydrogen and carbon black with zero CO₂ emissions, however careful control of the reactor is required to ensure product particles of specific sizes. A one-dimensional model employing a sectional method is developed to simulate the evolution of polydisperse fresh and seed particle populations in an indirectly heated solar reactor. The model accounts for the homogeneous nucleation of fresh particles, the heterogeneous growth of the fresh and seed particles, particle coagulation, and the growth of carbon on the walls of the reactor from heterogeneous reaction and particle deposition. The heat transport mechanisms modelled include wall-gas convection, wall-particle radiation exchange, particle-gas convection and heat release from chemical reaction. The model is validated in terms of methane conversion against a 10 kW experimental solar reactor and used to extract kinetic parameters for the homogeneous and heterogeneous reaction paths. The model shows promise as a quick and simple tool for the design and control of industrial scale solar reactors.     

A geometric nearest point algorithm for the efficient solution of the SVM classification task.

Geometric methods are very intuitive and provide a theoretically solid approach to many optimization problems. One such optimization task is the support vector machine (SVM) classification, which has been the focus of intense theoretical as well as application-oriented research in machine learning. In this letter, the incorporation of recent results in reduced convex hulls (RCHs) to a nearest point algorithm (NPA) leads to an elegant and efficient solution to the SVM classification task, with encouraging practical results to real-world classification problems, i.e., linear or nonlinear and separable or nonseparable.     

Effect of Feed Concentration on the Production of Pregelatinized Starch in a Double Drum Dryer

An industrial-scale double drum dryer is operated for producing pregelatinized maize starches using feed starch slurries of different solids content. Steam pressure, the level of pool between the drums and speed of drums rotation are varied together with the feed solids content in a practical range of values. The response of the dryer is registered by measuring several output variables, i.e. external drum temperature, product moisture content, mass flow rate and specific load (equivalent to product's film thickness). Experiments are also conducted with a different steam pressure in each drum and by preheating the feed slurry. The measurements of this work demonstrate for the first time that the concentration-dependent rheological and transport properties of the drying material dominate the drying process over and above the thermal condition of the drums. This information combined with the notion of thick momentum boundary layers surrounding the drums at the region of the gap are employed to explain the material application as a thin film over the drums.     

NEW DEVELOPMENTS IN THE BREWING INDUSTRY USING IMMOBILISED YEAST CELL BIOREACTOR SYSTEMS*

The use of immobilised yeast cell systems in industry has been extensively reported in the literature. The brewing industry is closely examining immobilisation technology and evaluating its merits. Various immobilisation methods are available to researchers and the nature of the application often dictates the choice of an immobilisation matrix. Industrial scale systems utilising immobilised yeast cells adsorbed to pre-formed carriers have been used for the production of low alcohol beers and for maturation or secondary fermentation of beer. Research relating to the primary fermentation of beer continues and several groups have developed laboratory scale systems. An overview of the respective technologies is provided and several relevant industrial applications cited .     

Energy evaluations during crack initiation

Experimental and analytical investigations of crack initation from single edge notched specimens of an amorphous polymer are reported. Experimental studies are aimed at observations of damage accumulation prior to crack initiation and the time to crack initiation under low cycle fatigue conditions. Under the particular conditions investigated here, two distinct patterns of crazing are observed: a core of crazes in front of the notch tip and peripheral, less dense crazes, which surround the core. The kinetics of the peripheral crazes resembles the behavior of short cracks observed in various materials. An abrupt change of the core craze zone is observed during a single loading cycle. This change in pattern suggests a drastic change in the stress field and is presumingly associated with the crack initiation event. For identical loading conditions the time to crack initiation is within experimental error. The analytical study involves the development of a numerical scheme for evaluation of the energy release rates due to the zone of damage prior to crack initiation. These energies are taken as the J and M integrals. The numerical scheme developed herein is based on experimentally measured craze openings and the technique of double layer potential. The results of the analysis show that while the M integral is positive and increases for both the core and the peripheral crazes, the value of J is negative and decreases for the core and increases positively for the peripheral crazes. The negative values of J are attributed to the fact that the core of crazes is embedded into an inhomogeneous stress field.     

Effects of strenuous exercise on serum myosin heavy chain fragments in male triathletes

The brewing yeast having glucoamylase activity was constructed by integrating glucoamylase cDNA from Asapergillus niger into the genome of brewing yeast B48. The integration was achieved by cotransformation of YEP type plasmid pKG1 carrying glucoamylase expression-secretion element and was verified by Southern blot analysis. The engineered yeast was stable, and the fermentation test demonstrated that the lower residual dextrin level was obtained compared with control strain B48. Thus the fermentation rate was raised to 80.5%. No alteration of growth and brewing properties was observed. Beer quality was judged to be good.     

A programmable array processor architecture for flexible approximate string matching algorithms

Approximate string matching problem is a common and often repeated task in information retrieval and bioinformatics. This paper proposes a generic design of a programmable array processor architecture for a wide variety of approximate string matching algorithms to gain high performance at low cost. Further, we describe the architecture of the array and the architecture of the cell in detail in order to efficiently implement for both the preprocessing and searching phases of most string matching algorithms. Further, the architecture performs approximate string matching for complex patterns that contain don’t care, complement and classes symbols. We also simulate and evaluate the proposed architecture on a field programmable gate array (FPGA) device using the JHDL tool for synthesis and the Xilinx Foundation tools for mapping, placement, and routing. Finally, our programmable implementation achieves about 8–340 times faster execution than a desktop computer with a Pentium 4 3.5 GHz for all algorithms when the length of the pattern is 1024.     

The effect of heat pretreatment temperature on fermentative hydrogen production using mixed cultures

The effect of heat treatment at different temperatures on two types of inocula, activated sludge and anaerobically digested sludge, was investigated in batch cultures. Heat treatments were conducted at 65, 80 and 95 °C for 30 min. The untreated inocula produced less amount of hydrogen than the pretreated inocula, with lactic acid as the main metabolite. The maximum yields of 2.3 and 1.6 mol H₂/mol glucose were achieved for the 65 °C pretreated anaerobically digested and activated sludges, respectively. Approximately a 15% decrease in yield was observed with increasing pretreatment temperature from 65 to 95 °C concomitant with an increase in butyrate/acetate ratio from 1.5 to 2.4 for anaerobically digested sludge. The increase of pretreatment temperature of activated sludge to 95 °C suppressed the hydrogen production by lactic acid fermentation. DNA analysis of the microbial community showed that the elevated pretreatment temperatures reduced the species diversity.     

Branched Poly(ε-caprolactone)-Based Copolyesters of Different Architectures and Their Use in the Preparation of Anticancer Drug-Loaded Nanoparticles

Limitations associated with the use of linear biodegradable polyesters in the preparation of anticancer nano-based drug delivery systems (nanoDDS) have turned scientific attention to the utilization of branched-chain (co-)polymers. In this context, the present study evaluates the use of novel branched poly(ε-caprolactone) (PCL)-based copolymers of different architectures for the preparation of anticancer nanoparticle (NP)-based formulations, using paclitaxel (PTX) as a model drug. Specifically, three PCL-polyol branched polyesters, namely, a three-arm copolymer based on glycerol (PCL-GLY), a four-arm copolymer based on pentaerythritol (PCL-PE), and a five-arm copolymer based on xylitol (PCL-XYL), were synthesized via ring-opening polymerization and characterized by proton nuclear magnetic resonance (¹H-NMR), gel permeation chromatography (GPC), intrinsic viscosity, differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier-transform infrared (FT-IR) spectroscopy and cytotoxicity. Then, PTX-loaded NPs were prepared by an oil-in-water emulsion. The size of the obtained NPs varied from 200 to 300 nm, while the drug was dispersed in crystalline form in all formulations. High encapsulation efficiency and high yields were obtained in all cases, while FTIR analysis showed no molecular drug polymer. Finally, in vitro drug release studies showed that the studied nanocarriers significantly enhanced the dissolution rate and extent of the drug.