Characterization of properties of oriented strand boards from beech and poplar

The aim of this study was to evaluate the possibility of using European beech and poplar species to manufacture oriented strand boards (OSB). Beech and poplar strands with three different combinations of face/core ratios at densities of 650 and 720 kg/m³ were examined. Poly methylene diphenyl diisocyanate glue at 5 % was used with press conditions of 180 °C and 240 s. Findings showed that with increasing density the physical and mechanical properties of the different OSB combinations generally improved. Panels made of 60 % beech in face layers showed higher modulus of rupture and modulus of elasticity. Internal bond strength rose as the amount of beech strands in the core layer increased. Panels with 75 % beech strands in the core layer showed the maximum internal bond strength at 720 kg/m³. It was also observed that increasing the amount of beech in the core layer from 40 to 75 % decreased thickness swelling at both densities.     

Biodiesel production using enzymatic transesterification - Current state and perspectives

Biodiesel has attracted considerable interest in recent years as an alternative, biodegradable and nonpolluting transportation fuel. Conventional alkaline process for biodiesel production are energy-consuming and generate undesirable by-products such as soaps, that make difficult the separation and purification of biodiesel.Particular attention has been dedicated to the use of lipases as biocatalysts for biodiesel production due to their favorable conversion rate obtained in gentle conditions and relatively simple downstream processing steps for the purification of biodiesel and by-products. However, comparatively to conventional chemical processes, the major obstacles for enzymatic production of biodiesel remain the cost of lipases, the relatively slower reaction rate and lipases inactivation caused by methanol and glycerol.This review evaluates the current status and perspectives for enzymatic biodiesel production and indicates the key operational variables that influence lipase activity and stability together with the technological solutions for industrial implementation of enzymatic process.     

Conjugated linoleic acid isomer concentrations in milk from high‐ and low‐input management dairy systems

BACKGROUND: Different conjugated linoleic acid (CLA) isomers are known to have contrasting physiology or health effects and there is growing evidence that the profile of natural isomers in milk is influenced by the production system. This survey is the first to compare feeding regimes and concentrations of 14 CLA isomers in milk from three production systems in the UK. RESULTS: Total CLA and seven isomers (including C18:2 c9t11 which comprised > 80% of total) were significantly higher in milk from both organically certified and non‐certified low input (LI) systems compared with milk from conventional high input farms. Sampling date also affected concentrations of total CLA and nine isomers; being lowest in March and highest in August. Seasonal differences were greater in milk from LI herds, thought to be due to changes in herbage and/or stage of lactation. Multivariate analysis showed a strong positive relationship between several CLA isomers and increasing levels of fresh forage in the diet. CONCLUSIONS: These results add to the evidence on how management adjustment may improve the profile of CLA isomers in milk fat, although animal or human intervention studies are required to identify the effects of consuming milk with different CLA levels and isomer profiles on human health. Copyright © 2009 Society of Chemical Industry     

Antifungal Activity of Lactic Acid Bacteria Isolated from Peanuts,Gari, and Orange Fruit Juice against Food Aflatoxigenic Molds

This study aims to evaluate the antifungal activity of lactic acid bacteria (LAB) from some Cameroonian food commodities against mycotoxigenic and spoilage molds. Following LAB isolation, the antifungal activity of the isolates was assessed. The organic acids were quantified using high-performance liquid chromatography and the ability of the LAB to reduce mold biomass and aflatoxin production was evaluated. The LAB were identified and the biopreservative potential of strain LO3 was evaluated on tomato paste. Nine percent of the strains isolated showed broad antifungal activity. The activity was due to the effect of organic acids comprising lactic, acetic, 4-hydroxy-3-phenyllactic and 3-phenyllactic acids. Lactobacillus plantarum LO3 exhibiting the highest and broadest antifungal activity was selected and showed the capacity to inhibit fungal growth and aflatoxin production in vitro. Moreover, this strain and its cell-free supernatant showed the ability to prevent aflatoxigenic mold growth in tomato paste without altering its physico-chemical and organoleptic properties.     

Fast start-up of a diesel fuel processor for PEM fuel cells

Fuel cell systems based on liquid fuels are particularly suitable for auxiliary power generation due to the high energy density of the fuel and its easy storage. Together with industrial partners, Oel-Waerme-Institut is developing a 3 kW_el PEM fuel cell system based on diesel steam reforming to be applied as an APU for caravans and yachts. The start-up time of a fuel cell APU is of crucial importance since a buffer battery has to supply electric power until the system is ready to take over. Therefore, the start-up time directly affects the battery capacity and consequently the system size, weight, and cost.     

Coking behavior of nickel and a rhodium based catalyst used in steam reforming for power-to-gas applications

This paper proposes partial steam reforming of natural gas as a chemical storage option for excess electricity. Thermodynamic simulations with Aspen Plus^® show that highest process efficiencies are reached at low steam-to-carbon (S/C) ratios in the feed. However, coke deposition due to unwanted side or follow-up reactions and thus catalyst deactivation is likely in this operation range. In an experimental evaluation three catalysts were selected to test their resistance towards coking: two nickel based and one rhodium based noble metal catalyst. They were tested regarding their long-term stability at S/C ratios as low as 0 to 0.1 and reaction temperatures between 450 and 500 °C. A different reaction and deactivation behavior was observed for nickel and the noble metal catalysts. The measured life times of the noble metal catalyst were by a factor of at least 100 higher than for the two selected nickel catalysts at the applied reforming conditions. Furthermore, after each reforming experiment, a temperature-programmed oxidation (TPO) analysis was performed for the spent catalysts. Based on literature data, the measured CO₂ peaks at corresponding temperatures were related to the different forms of solid carbon depositions. Main carbonaceous species found on the nickel catalysts were of filamentous nature, whereas one or two more reactive C species with monoatomic or polymeric structure at much lower amount were detected on the noble metal catalyst. Further SEM analysis confirmed these findings.     

Prediction of highway lane changes based on prototype trajectories

Forschung im Ingenieurwesen - The vision of automated driving is to increase both road safety and efficiency, while offering passengers a convenient travel experience. This requires that...     

Viologen capped by nucleobase—building blocks for functional materials: synthesis and structure–properties relationship

Journal of Materials Science - The current study presents a new class of functional derivatives (1–3) consisting of a dicationic viologen (4,4’-bipyridinium unit) (V2+) capped by...     

Site-directed mutants of the cAMP receptor protein-DNA binding of five mutant proteins

Oligonucleotide-directed mutagenesis was employed to generatemutants of the cAMP receptor protein (CRP) of Escherichia coli.The mutant proteins were purified to homogeneity and testedfor stability and DNA binding. It is shown that mutations atthe position of Arg¹⁸⁰ abolish specific DNA binding, whereasthose at the position Arg¹⁸⁵ have very little effect. Both positionshave previously been implicated as crucial for the specificinteraction between CRP and DNA. The Ser¹²⁸ Ala mutant showsa slight reduction in DNA binding affinity relative to wild-type.All mutants investigated show similar stability profiles towild-type CRP with respect to thermolysin proteolysis as a functionof temperature.