Hydrogen production from methane in a dielectric barrier discharge using oxide zinc and chromium as catalyst

The hydrogen fuel cell is a promising option as a future energy resource; however, the nature of the gas is such that the conversion process of other fuels to hydrogen on board is necessary. Among the raw fuel resources, methane could be the best candidate as it is plentiful. In this experiment, the possibility of producing hydrogen with less carbon formation from methane by a dielectric barrier discharge (DBD) was investigated. Without the addition of a catalyst, the formation of hydrogen reached between 30% and 35% at methane residence time of 0.22 min and supplied powers in the range of 60-130 W. The hydrogen selectivity increased at higher supplied power, but the process efficiency, defined as a ratio of the produced hydrogen to the supplied power, decreased slightly. In order to boost the hydrogen production with less carbon formation, a mixed oxide catalyst of zinc and chromium was added to the reactor. It was shown that the production of hydrogen was ca. 40% higher than the non-catalytic plasma process.     

Simulation of temperature and reaction time prediction of the torrefaction process: case of hard-wood biomass

Direct utilisation of biomass for energy application is less profound due to the problems of low calorific value, high water content, and low grindability of biomass. For this reason, pre-heating treatment, sometimes called torrefaction, is necessary to improve the physical properties of biomass similar to ‘coal-like’ material. Unfortunately, only few comprehensive but simple theoretical models focused on hard-wood biomass were available to describe the torrefaction process. In this discussion, a simple proposed torrefaction model was developed and reported. The model has ability to estimate the yield of product mass and energy after the torrefaction process and determine the optimum conditions.     

Analysing supply chain performance using a balanced measurement method

Aside from lean management and business process re-engineering, a new management approach for optimizing logistics organization is gaining recognition: supply chain management.An essential precondition to benefit from supplychain management is a structured analysis of the network-specific optimization opportunities. Opportunities are derived from suboptimal inner- and cross-organisational business processes and the related material, information and capital flows. The paper describes a supply chain analysis approach and proposes a measurement methodology integrating bottom-up and top-down performance measures as a hybrid balanced measurement approach.     

Molecular cloning and characterization of a thermostable α-amylase exhibiting an unusually high activity

An α-amylase gene was cloned from the thermophilic bacterium Bacillus subtilis isolated from Indonesian oil palm shell waste. The gene expressed an extracellular enzyme. Optimal hydrolysis conditions for the enzyme were 70°C and pH 6.0. The specific activity of the enzyme was 16.0 kU per mg of protein, which was higher than for other thermostable amylases. Hydrolytic products of the enzyme using starch and glycogen were mainly maltohexaose and maltopentaose. The enzyme had a K _m value of 0.099 mg/mL for amylopectin, more than 10 times lower than for amylose. The catalytic efficiency of the enzyme using amylopectin was 39,200 mL/mg·s and was 3,270 mL/mg·s using amylose. The enzyme liquefied corn starch at pH 5.0, which was successfully converted to glucose using commercial glucoamylase and pullulanase without pH adjustment. The enzyme has advantages for industrial applications.     

Decorrelation-based blood flow velocity estimation: effect of spread of flow velocity,linear flow velocity gradients,and parabolic flow

In recent years, a new method to measure transverse blood flow, based on the decorrelation of the radio frequency (RF) signals has been developed. In this paper, we investigated the influence of nonuniform flow on the velocity estimation. The decorrelation characteristics of transverse blood flow using an intravascular ultrasound (IVUS) array catheter are studied by means of computer modeling. Blood was simulated as a collection of randomly located point scatterers; moving this scattering medium transversally across the acoustical beam represented flow. First-order statistics were evaluated, and the signal-to-noise ratio from the signals were measured. The correlation coefficient method was used to present the results. Three velocity profiles were simulated: random spread of blood-flow velocity, linear blood-flow velocity gradient, and parabolic blood-flow. Radio frequency and envelope signals were used to calculate the decorrelation pattern. The results were compared to the mean decorrelation pattern for plug blood-flow. The RF signals decorrelation patterns were in good agreement with those obtained for plug blood flow. Envelope decorrelation patterns show a close agreement with the one for plug blood flow. For axial blood flow, there is a discrepancy between decorrelation patterns. The results presented here suggest that the decorrelation properties of an IVUS array catheter for measuring quantitative transverse blood flow probably will not be affected by different transverse blood-flow conditions     

In vitro gas production profiles and fermentation end‐products in processed peas,lupins and faba beans

BACKGROUND: An experiment was carried out to establish whether using a pre‐compacting device (expander) changes the contribution of dry matter (DM) and degradative behaviour of peas, lupins and faba beans over the different fractions (non‐washable fraction, NWF; insoluble washable fraction, ISWF; soluble washable fraction, SWF). Samples of the entire concentrate ingredients (WHO ingredients) and their different fractions (NWF, ISWF and SWF) were subjected to three processes (Retsch milling, R; expander treatment, E; expander‐pelleting, EP) and their fermentation characteristics were evaluated using an in vitro gas production technique. RESULTS: In peas and faba beans, both the E and EP processes increased the size of the NWF (P < 0.05) and decreased the size of the SWF compared with the R process. The maximum fractional rate of gas production in the first phase of fermentation was higher in the E and EP samples than in the R samples (P < 0.05). In lupins and faba beans the E and EP processes shifted the pattern of fermentation towards a more glucogenic fermentation, as represented by a lower non‐glucogenic to glucogenic ratio (NGR). Ammonia production (NH₃‐N) in the E and EP samples was significantly (P < 0.05) lower than that in the R samples. CONCLUSION: It is concluded that the E and EP processes provide a certain level of protection against ruminal breakdown to dietary protein and shift the pattern of fermentation towards a more glucogenic fermentation. Copyright © 2008 Society of Chemical Industry     

Influence of plasticizer with different functional groups on thermoplastic starch

Retrogradation of amorphous thermoplastic starch (TPS) films obtained by compression molding of spray dried modified potato starch was investigated. The aim was to investigate the influence of plasticizers with similar molecular weight but different functionality, i.e., isoleucine, asparagine and malic acid, on the properties of plasticized powder and TPS films. Combinations of malic acid with glycerol, urea, and maltodextrin were also evaluated. Except for isoleucine formulated starch, all samples were obtained as amorphous powders and films. Malic acid was identified as a strong antiretrogradation agent as it inhibited recrystallization of starch over the full range of humidity levels. Malic acid was also found to inhibit the retrogradation of formulations containing urea, glycerol and maltodextrin. The converse of the strong inhibition implied strong moisture absorption and high strain at break values, and low tensile strengths. Malic acid was also identified as a potential crosslinking agent to control swelling of starch‐based products. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42012.     

DFT studies of hydrogen storage properties of Mg0.75Ti0.25

Absorption energies of hydrogen in Mg_0.75Ti_0.25 alloys as a function of the hydrogen concentration were calculated using Density Functional Theory. Four types of structures of alloys and their hydrides including TiAl₃, ZrAl₃, AuCu₃, and segregated types of structures were considered. The stability of the configurations, and the structural and electronic bonding properties were studied. The hydrogenation properties depend highly on the structure of the alloys. The ordered alloys have very similar properties to that of pure Mg. For segregated alloys, the hydrogenation properties can be divided to Ti-like, ordered alloy-like and Mg-like from low to high hydrogen concentration. The formation energies show that for the four structures, segregated Mg_0.75Ti_0.25 is favored for alloys, whereas TiAl₃ type of Mg_0.75Ti_0.25H₂ are favored for hydrides. Therefore hydrogen induced structural rearrangement of the intermetallic structures of the Mg_0.75Ti_0.25 might occur upon hydrogen cycling. For the non-homogenous Mg-Ti-H system, further phase segregation of Ti in Mg might occur. Partial dehydrogenation with some hydrogen remaining in the Ti-rich region may improve reversibility.     

Achievable PID performance using sums of squares programming

In addition to process elements like time delay, the PID structure of the controller can pose fundamental limitations on the achievable control performance. A key difficulty in characterizing the limitations due to controller structure is the non-convexity of the resulting optimization problem. In this paper, we present a global lower bound on the achievable PID performance, defined in terms of output variance, by solving a series of convex programs using sums of squares programming. This result is also extended to minimize the weighted sum of the variances of input rate and output. The tightness of the proposed bounds is demonstrated using several benchmark examples drawn from literature.     

Molecular dynamics simulations as a tool for improving protein stability

Haloalkane dehalogenase (DhlA) was used as a model protein toexplore the possibility to use molecular dynamics (MD) simulationsas a tool to identify flexible regions in proteins that canserve as a target for stability enhancement by introductionof a disulfide bond. DhlA consists of two domains: an