The tree species matters: Biodiversity and ecosystem service implications of replacing Scots pine production stands with Norway spruce

Ambio - The choice of tree species used in production forests matters for biodiversity and ecosystem services. In Sweden, damage to young production forests by large browsing herbivores is helping...     

Pleasure in using adaptive cruise control: A questionnaire study in The Netherlands

Objective: Adaptive cruise control (ACC), a technology that allows for automated car following, is becoming increasingly prevalent. Previous surveys have shown that drivers generally regard ACC as pleasant but that they have to intervene when the ACC reaches its operational limits. The former research has been mostly concerned with specific car brands and does not fully reflect the diversity of ACC types in traffic today. The objective of the present research was to establish the determinants of pleasure in using ACC.

Methods: A 55-item online questionnaire was completed by Dutch users of diverse ACC systems.

Results: Respondents (N = 182) rated their ACC highly, with a mean score of 8.0 on a scale from 1 (extraordinarily negative) to 10 (extraordinarily positive) and were most pleased with ACC on high-speed roads and in low-density traffic. Moreover, the findings point to specific operational limits such as associated with cut-in situations. Pleasure was greater for the types of ACC that are able to decelerate to a full stop, according to 48% of our sample. An analysis of the free-response items indicated that respondents who were displeased with ACC mentioned its occasional clumsiness and the dangerous situations it may evoke, whereas those who were pleased with ACC valued the complementarity of human and machine and emphasized the roles of responsibility and experience in using ACC.

Conclusion: Pleasure in using ACC is a function of both technological advances and human factors.     

Revisions to the derivation of the Australian and New Zealand guidelines for toxicants in fresh and marine waters

The Australian and New Zealand Guidelines for Fresh and Marine Water Quality are a key document in the Australian National Water Quality Management Strategy. These guidelines released in 2000 are currently being reviewed and updated. The revision is being co-ordinated by the Australian Department of Sustainability, Environment, Water, Population and Communities, while technical matters are dealt with by a series of Working Groups. The revision will be evolutionary in nature reflecting the latest scientific developments and a range of stakeholder desires. Key changes will be: increasing the types and sources of data that can be used; working collaboratively with industry to permit the use of commercial-in-confidence data; increasing the minimum data requirements; including a measure of the uncertainty of the trigger value; improving the software used to calculate trigger values; increasing the rigour of site-specific trigger values; improving the method for assessing the reliability of the trigger values; and providing guidance of measures of toxicity and toxicological endpoints that may, in the near future, be appropriate for trigger value derivation. These changes will markedly improve the number and quality of the trigger values that can be derived and will increase end-users’ ability to understand and implement the guidelines in a scientifically rigorous manner.     

Treatment of wastewater from red and tropical fruit wine production by zeolite anaerobic fluidized bed reactor

A study of the anaerobic treatment of wastewaters derived from red (RWWW) and tropical fruit wine (TFWWW) production was carried out in four laboratory-scale fluidized bed reactors with natural zeolite as bacterial support. These reactors operated at mesophilic temperature (35°C). Reactors R1 and R2 contained Chilean natural zeolite, while reactors R3 and R4 used Cuban natural zeolite as microorganism support. In addition, reactors R1 and R3 processed RWWW, while reactors R2 and R4 used TFWWW as substrate. The biomass concentration attached to zeolites in the four reactors studied was found to be in the range of 44–46 g volatile solids (VS)/L after 90 days of operation time. Both types of zeolites can be used indistinctly in the fluidized bed reactors achieving more than 80%–86% chemical oxygen demand (COD) removals for organic loading rates (OLR) of up to at least 20 g COD/L d. pH values remained within the optimal range for anaerobic microorganisms for OLR values of up to 20 and 22 g COD/L d for RWWW and TFWWW, respectively. Toxicity and inhibition levels were observed at an OLR of 20 g COD/L d in reactors R1 and R3 while processing RWWW, whereas the aforementioned inhibitory phenomena were not observed at an OLR of 24 g COD/L d in R2 and R4, treating TFWWW as a consequence of the lower phenolic compound content present in this substrate. The volatile fatty acid (VFA) levels were always lower in reactors processing TFWWW (R2 and R4) and these values (< 400 mg/L, as acetic acid) were lower than the suggested limits for digester failure. The specific methanogenic activity (SMA) was twice as high in reactors R2 and R4 than in R1 and R3 after 120 days of operation when all reactors operated at an OLR of 20 g COD/L d.     

Emission Factors for Gasoline Light-Duty Vehicles: Experimental Program in Santiago,Chile

ABSTRACT

The emission inventory of the city of Santiago, Chile, related to mobile sources was built up using constant emission factors extracted from international literature. To improve the estimate of mobile source emissions, an experimental program was designed, consisting of transient tests on a chassis dynamometer over a sample of about 166 vehicles, applying 9 local driving cycles with average speeds of 3-80 km/hr, and experimentally determined in previous research carried out by the authors. An analysis of the influence of fuel inlet technology, and a year time-length model over emissions, was undertaken. We proposed emission factors as a function of average speed and of CO, THC, and NO_x for catalytic and noncatalytic light-duty gasoline vehicles, disaggregated on commercial and private cars. A comparative analysis with emission factors obtained for the application of the COPERT II and AP-42 models was also presented. Our current analysis gives solid evidence indicating that to obtain a reasonable accuracy on emission estimates and calculations, local emission factors must be used.     

Desulfurization of Flue Gases in A Fluidized Bed of Modified Limestone

This publication concerns the dry removal of SO₂ from gases using limestone absorbents. It reports bench-scale experiments made with commercial samples of powdered limestone (CaCO₃) activated by addition of a cheap substance, namely CaCl₂. The absorption was carried out in a fluidized bed traversed by the flue gases, between 600° and 900° C. The degree and rate of transformation of CaCO₃ to CaSO₄ in the presence of SO₂ and air have been compared for unmodified and modified absorbents. Initial rates of reaction, and the variation of the rate of absorption with time have been measured. The influence of the SO₂ content of the gas has been assessed. At 700° C, the maximum degree of transformation of activated limestone to sulfate exceeds 90%, whereas untreated CaCO₃ transforms only to 16–20%. At the same temperature, more than 90% of SO₂ contained In a gas carrying 0.35% SO₂ is removed. Because of the much smaller quantity of solid absorbent required, dry absorption processes based on the modified absorbents might get renewed interest. The modified absorbents might also be used for in situ absorption in fluidized bed combustion, in which the temperatures are in the range studied in the present paper.     

Assessing safety culture in the Spanish nuclear industry through the use of working groups

This paper presents the design and the implementation of a methodology for measuring and improving safety culture at a nuclear power plant (NPP). The study has involved the completion of a pilot project aimed at seeing how to make use of the RADAR logic (Results, Approach, Deployment, Assessment and Review) of the EFQM model as a tool for the self assessment of safety culture in a nuclear power plant. The work was aimed at finding evidence of the safety culture that was in place at the plant and at identifying both the strengths of that culture and any areas in which it could be improved. The score obtained from an analysis of those strengths and areas for improvement has made it possible to prioritise the actions to be taken. The identification of perceptions and evidence, the agreement on the strong points and areas for improvement and the quantification of the safety culture have been performed by groups comprising volunteers who work at the NPP. The advantages of this methodology are assessed in the paper.