Response on the ground of bark beetle and weevil species colonizing conifer stumps and roots to terpenes and ethanol

Responses of threeHylastes species,Dryocoetes autographus, and twoHylobius species to terpenes and ethanol were studied in field experiments on clear-cut forest sites in Sweden using baited ground traps.-Pinene alone did not attract any of the six species. A terpene blend (spruce turpentine consisting mainly of-pinene,-pinene, and 3-carene) attractedHylastes cunicularius, H. brunneus, andHylobius abietis in some experiments, but not in others. The attractiveness of ethanol also varied; the only species consistently attracted wasH. abietis. Baits containing both terpenes and ethanol, particularly the combination of spruce turpentine and ethanol, were attractive to all species exceptHylobius pinastri. InH. abietis, the terpene plus ethanol/ ethanol catch ratios increased during early summer. Seasonal differences in catch levels were observed inH. cunicularius andH. abietis. The addition of-pinene reduced the attractiveness of the combination of spruce turpentine and ethanol toH. cunicularius, H. opacus, andD. autographus. The differences in response to the volatiles between species are probably related to differences in reproductive behavior and host preferences.     

Ni foam cathode enables high volumetric H2 production in a microbial electrolysis cell

Valuable, “green” H₂ can be produced with a microbial electrolysis cell (MEC). To achieve a high volumetric production rate of high purity H₂, a continuous flow MEC with an anion exchange membrane, a flow through bioanode and a flow through Ni foam cathode was constructed. At an electrical energy input of 2.6 kWh m⁻³ H₂ (applied cell voltage: 1.00 V), this MEC was able to produce over 50 m³ H₂ m⁻³ MEC d⁻¹ (22.8 ± 0.1 A m⁻²). The MEC had a low cathode overpotential compared to an MEC with Pt-based cathode, because of the high specific surface area of Ni foam (128 m² m⁻² projected area). The MEC performance however, decreased during 32 days of operation due to an increase in anode and cathode overpotentials. Scaling likely caused the increase in anode overpotential, but it remained unclear what caused the increase in cathode overpotential.     

Capacitive bioanodes enable renewable energy storage in microbial fuel cells

We developed an integrated system for storage of renewable electricity in a microbial fuel cell (MFC). The system contained a capacitive electrode that was inserted into the anodic compartment of an MFC to form a capacitive bioanode. This capacitive bioanode was compared with a noncapacitive bioanode on the basis of performance and storage capacity. The performance and storage capacity were investigated during polarization curves and charge-discharge experiments. During polarization curves the capacitive electrode reached a maximum current density of 1.02 ± 0.04 A/m(2), whereas the noncapacitive electrode reached a current density output of only 0.79 ± 0.03 A/m(2). During the charge-discharge experiment with 5 min of charging and 20 min of discharging, the capacitive electrode was able to store a total of 22,831 C/m(2), whereas the noncapacitive electrode was only able to store 12,195 C/m(2). Regarding the charge recovery of each electrode, the capacitive electrode was able to recover 52.9% more charge during each charge-discharge experiment compared with the noncapacitive electrode. The capacitive electrode outperformed the noncapacitive electrode throughout each charge-discharge experiment. With a capacitive electrode it is possible to use the MFC simultaneously for production and storage of renewable electricity.     

Modelling of a pin-fin heat converter with fluid cooling for power semiconductor modules

This paper presents a way to design a finite-element computer model of cooling system with a complicated geometry. The computer model is developed on the basis of a commercial software package ABAQUS. The steady state forced-convective fluid cooling of a pin-fin heat converter for power (∼1 kW heat power) semiconductor module has been investigated on the basis of computer simulation. A phenomenological equation has been used for calculation of the local value of the heat transfer coefficient for the liquid-solid interface. The impacts of the thermal conductivity of the pin-fin sink material, volume flow rate of the cooling liquid and geometrical design of the pin-fin sink on the thermal resistance of the converter are shown. Copyright © 2003 John Wiley & Sons, Ltd.     

Increase of power output by change of ion transport direction in a plant microbial fuel cell

The plant microbial fuel cell (PMFC) is a technology for the production of renewable and clean bioenergy based on photosynthesis. To increase the power output of the PMFC, the internal resistance (IR) must be reduced. The objective of the present study was to reduce the membrane resistance by changing the transport direction of cations in the direction of the established concentration gradient. Two setups, a MFC and PMFC, were designed with one anode and two cathode compartments to demonstrate the effect of changing the transport direction. This design allowed changing the direction of transport of cations by switching the cathode compartment that functions as cathode. The change between cathode 1 and cathode 2 enhanced the power output of the PMFC by 398%. More specifically, after changing transport direction, the increase in power output was due to the reduction of IR (normalized to membrane area) from 4.3 Ω m²_mem to 1.2 Ω m²_mem in the PMFC. Consecutive changes of cathodes resulted in an increase of generated power with cathode 1 while this power decreased for cathode 2. During the consecutive changes, the average power output remained constant 0.0362 ± 0.0005 W m^?2_mem; this was 246% higher than the initial power output with cathode 1. Copyright © 2012 John Wiley & Sons, Ltd.     

Shocks in economic growth = shocking effects for food security?

The recent economic and financial turmoil raises the question on how global economic growth affects agricultural commodity markets and, hence, food security. To address this question, this paper assesses the potential impacts of faster economic growth in developed and emerging economies on the one hand and a replication of the recent economic downturn on the other hand. The empirical analysis uses AGLINK-COSIMO, a recursive-dynamic, partial equilibrium, supply–demand model. Simulation results demonstrate that higher economic growth influences demand more than supply, resulting in higher world market prices for agricultural commodities. Emerging economies tend to import more and to stock less in order to cover their demand needs, while the rest of the world increases its exports. The modelled faster economic growth also helps developing countries to improve their trade balance, but does not necessarily give them the incentive to address domestic food security concerns by boosting domestic consumption. A replication of an economic downturn leads to lower world prices, and while the magnitude of the effects decreases over time, markets do not regain their baseline levels within a 5-year period. Due to the lower world market prices, developing countries import more and increase their per capita food calorie intake. However, as developing countries become more import dependent, this also implies that they become more vulnerable to disruptions in agricultural world markets.     

Analytical determination of compounds released during pyrolysis,smoldering, and combustion experiments with insulation materials from renewable resources

Obviously, the use of insulation materials from renewable resources in buildings could provide benefits regarding environmental protection and sustainable management. Nevertheless, their market share in Germany is estimated to be about 7% because of a partial lack of knowledge about their properties, and therefore, of construction certifications. This work was intended to close a knowledge gap concerning emissions during pyrolysis, smoldering, and combustion of commercial insulating materials made from wood, cellulose, meadow grass, hemp, jute, cork, and seaweed as well as polystyrene for comparison reasons. Laboratory-scale experiments were conducted and the measurement of thermal decomposition products was done with gas chromatography combined with mass spectrometry (GC/MS). It was realized that almost all the products could be assigned to the following eight substance classes: carbohydrates, aldehydes/ketones, carbonic acids/esters, substituted phenols, furans, aliphatic hydrocarbons, substituted benzenes, and polycyclic aromatic hydrocarbons. Substance spectra were generated that showed certain conformities, especially between the insulating materials made from wood, cellulose, and meadow grass as well as hemp and jute. Comparisons of the sum of peak areas in the GC/MS-chromatograms provided indications of the relative extent of thermal decomposition product emissions. Calculations according to (∑peak areas _{renewable material})/(∑peak areas _polystyrene) revealed factors between 0.18 (wood, cork) and 0.028 (meadow grass). In the thermal emissions, defined hazardous substances or substance groups were frequently measured. These were included in a toxicity evaluation by which, inter alia, advantages of the natural products compared to polystyrene could be demonstrated.     

SAFT-γ Mie model for ionic liquids

The SAFT-γ Mie model is a recent version of statistical associating fluid theory (SAFT), which uses a group contribution approach to obtain a high-quality equation of state. In this work, this model is, for the first time, extended to ionic liquids (ILs). The SAFT-γ Mie calculated values agree well with the experimental data for one-component, binary and ternary systems that contain ILs, thus indicating the versatility and accuracy of this extension.     

Increase of platinum group element concentrations in soils and airborne dust in an urban area in Germany

Since 1993, all new cars sold in the European Union had to be fitted with catalytic converters. Undoubtedly, these measures brought about a great progress concerning traffic emission controls. However, this technology also led to new emissions. A rapid accumulation of the catalytic active noble metals Pt, Pd, and Rh in the environment was observed and concern arose about potential environmental and health risks. This work aimed at a contribution to a monitoring of platinum group element (PGE) emission and accumulation by comparing analytical data, all generated in 1999 and in 2005 in an urban area in Germany. Oriented at the 1999 sampling strategy, soil and airborne dust samples were taken in 2005 at the same sampling sites located mainly close to heavily used roads in the region of Braunschweig. For the enrichment of the analytes, conditioned soil samples as well as loaded glass fiber filters from air sampling were transferred to the nickel sulphide fire assay. For analyses, the ICP-MS technique was applied. High Pt, Pd, and Rh concentrations were detected especially in top soil layers (0-2 cm) directly at the roadsides or on center strips. At one road outside the city, where traffic moved with a constant speed of about 80 km/h, maximum concentrations in soil were found to be 50.4 microg/kg for Pt, 43.3 microg/kg for Pd, and 10.7 microg/kg for Rh. PGE concentrations were the highest close to that road and exponentially declined with growing distance. At a second road, where vehicles run with a constant speed of 50 km/h, the highest concentrations were detected in the center strip soil: 88.9 microg/kg (Pt), 77.8 microg/kg (Pd), and 17.6 microg/kg (Rh). At a third crowded street in the centre of Braunschweig with stop and go traffic, the highest soil concentrations were determined, namely 261 microg/kg for Pt, 124 microg/kg for Pd and 38.9 microg/kg for Rh. The sampling of airborne dust at this roadside revealed for Pt 159 pg/m(3) air or 1730 microg/kg dust, for Pd 37.8 pg/m(3) air or 410 microg/kg dust, and for Rh 10.0 pg/m(3) air or 110 microg/kg dust. A comparison of analytical results of 2005 with those of 1999 revealed a distinct increase of PGE concentrations in soils closely along heavy traffic roads by a factor of 2.1 to 8.9; once even a factor of 15 was determined. The findings also document, that especially Pt and Rh concentrations were elevated in airborne dust.