A comparative study on the effect of GTAW processes on the microstructure and mechanical properties of P91 steel weld joints

Modified 9Cr-1Mo (P91) steel is widely used in the construction of power plant components. In the present study, a comparative study on influence of activated flux tungsten inert gas (A-TIG), and gas tungsten arc (GTA) welding processes on the microstructure and the impact toughness of P91 steel welds was carried out. P91 steel welds require a minimum of 47 J during the hydrotesting of vessels as per the EN1557: 1997 specification. Toughness of P91 steel welds was found to be low in the as-weld condition. Hence post-weld heat treatment (PWHT) was carried out on weld with the objective of improving the toughness of weldments. Initially as per industrial practice, PWHT at 760 °C – 2 h was carried out in order to improve the toughness of welds. It has been found that after PWHT at 760 °C – 2 h, GTA weld (132 J) has higher toughness than the required toughness (47 J) as compared with A-TIG weld (20 J). The GTA weld has higher toughness due to enhanced tempering effects due to multipass welding, few microinclusion content and absence of δ-ferrite. The A-TIG weld requires prolonged PWHT (i.e. more than 2 h at 760 °C) than GTA weld to meet the required toughness of 47 J. This is due to harder martensite, few welding passes that introduces less tempering effects, presence of δ-ferrite (0.5%), and more alloy content. After PWHT at 760 °C – 3 h, the toughness of A-TIG weld was improved and higher than the required toughness of 47 J.     

Correlating negotiation hotspot issues,Paris climate agreement and the international climate policy regime

The concerns over climate change negotiation, decision texts and links to domestic policy interests of countries to keep warming within an acceptable limit have become the ‘hotspot issues’ of the United Nations Framework Convention on Climate Change (UNFCCC). Hotspot issues are the human – political economy factors which have evolved over time from negotiation texts or phrases, principles or behaviors with tendencies to influence climate negotiations yet cannot be identified with the scientific literature. Whilst big emitters have been accused as having hegemony over the negotiations, the effects of disunity amongst the parties over domestic policy interests have been overlooked. Hence the article examines the emergence of hotspot issues and how they manifest within the international climate policy regime. The Intended Nationally Determined Contributions (INDCs) of 130 countries submitted before the Paris agreement, were analyzed using the following texts: Adaptation, Mitigation, Co-benefits, Finance, Land use, Food security, Poverty, Resilience, Green growth, Green economy, Sustainable development, Biodiversity, Ecosystem services and Conservation. Of these, ‘adaptation’ was cited 2780 times, 1956 for ‘mitigation’ and 32 for ‘ecosystem services’ in the nature conservation category. Ten phases of the climate policy regime and historical hotspot issues were identified for the period 1980–2030. ‘Adaptation’ and mitigation appeared more frequently in the INDCs and correlated with each other (r = 0.56), as the two correlated further with ‘land use’ (0.50 < r < 0.60), and similarly with sustainable development (0.40 < r < 0.70) where ‘r’ is the Pearson Rank Correlation. Therefore the success of the ‘ambitious targets’ for mitigation will depend on similar ambitious goals for adaptation, land use and sustainable development. Several differences existed in the correlation of the hotspot issues within the regional geographical blocs (Africa, Asia, Europe, North America, Oceania, South America) and split along the hotspot issues yet Europe mostly oriented towards mitigation and land use, and Oceania on resilience building. These differences provide favorable conditions for increased cooperation and true multilateralism if they are properly diagnosed.     

A new tool to map the major worldviews in the Netherlands and USA,and explore how they relate to climate change

For addressing climate change, public support for changes in policy is needed, as well changes in individual lifestyles. Both of these appear to be intimately related with people’s worldviews. Understanding these worldviews is therefore essential. In order to research and ‘map’ them, we translated the theoretical ‘Integrative Worldview Framework’ (IWF) into an empirical, quantitative approach. We constructed a worldview-scale aiming to distinguish between four major worldviews – labeled traditional, modern, postmodern, and integrative – and explored their interface with opinions and behaviors with respect to climate change. The survey was conducted with representative samples of citizens in the Netherlands and the USA (n = 527 and n = 556). The hypothesized worldviews were found in the data with a reasonable degree of reliability, especially in the Dutch sample. We also found consistent relationships between these worldview-clusters and a range of opinions, political priorities, and behaviors. In both countries postmoderns and integratives displayed significantly more concern about climate change as well as more sustainable behaviors, compared with moderns and traditionals. The implications of these findings for environmental policy and social science are noteworthy.     

Impact caps: why population,affluence and technology strategies should be abandoned

This paper classifies strategies to reduce environmental impact according to the terms of the I = PAT formula. Policies limiting resource depletion and pollution (Impact) – by heavily taxing resources or rationing them on a country basis – are thus called ‘direct’ or ‘left-side’ strategies. Other policies to achieve the environmental goal of lowering Impact strive to limit Population and Affluence, or to use Technology to lower the ratio of resource inputs to goods-and-services outputs. Next it is shown that lowering any of these ‘right-side’ factors causes or at least enables the other two to rise or ‘rebound’. This has two consequences: 1) Since I = PAT does not express these interdependencies on the right side, it is more accurately written I = f(P,A,T); and 2) Success in lowering any of the right-side factors does not necessarily lower Impact. Rationing or Pigouvian taxation of resources or pollution, on the other hand, necessarily lower impact and are therefore preferable to population, consumption and technological environmental strategies. Finally, lifestyle and technology changes towards more sufficiency and efficiency would follow the caps as consumers and producers work to retain the greatest amount of welfare within the limits given.     

Comparison of registry methodologies for reporting carbon benefits for afforestation projects in the United States

No mandatory national program currently exists to mitigate climate change in the US Consequently, voluntary programs and mandatory state-level programs are multiplying to allow users to register emission-offset activities, creating multiple often contradictory measurement and recording standards.For the land use sector we examined a hypothetical project: tree planting on rangelands in California. We apply four sets of protocols from the following registries – the California Climate Action Registry, the Chicago Climate Exchange (CCX), the Regional Greenhouse Gas Initiative and the USDOE 1605(b) program – and compare the results to the ‘actual’ net sequestration and also briefly compare them to international protocols such as the relevant Clean Development Mechanism methodology. Carbon in land use can be estimated accurately, precisely and cost-effectively, but to achieve this requires good protocols. As predicted, the consequence of applying different protocols for reportable carbon was significant. The choice of measurement pools, the handling of the baseline and the issue of uncertainty led to a baseline estimate of 0–66,690 t CO₂-e, and final sequestered carbon totals (after 60 years) that varied between 118,044 and 312,685 t CO₂-e—a factor of 2.5 difference. The amount reported under 1605(b) is the closest to “actual” with CCX entity reporting the most divergent.     

Exceedance of modern ‘background’ fine-grained sediment delivery to rivers due to current agricultural land use and uptake of water pollution mitigation options across England and Wales

Excessive loss of fine-grained sediment to rivers is widely recognised as a global environmental problem. To address this issue, policy teams and catchment managers require an estimate of the ‘gap’ requiring remediation, as represented by the excess above ‘background’ losses. Accordingly, recent work has estimated the exceedance of modern ‘background’ sediment delivery to rivers at national scale across England and Wales due to (i) current agricultural land cover, cropping and stocking, and (ii) current land use corrected for the uptake of on-farm mitigation measures. This sectoral focus recognises that, nationally, agriculture has been identified as the principal source of fine sediment loss to the aquatic environment. Two estimates of modern ‘background’ sediment loss, based on paleolimnological evidence, were used in the analysis; the target modern ‘background’ (TMBSDR) and maximum modern ‘background’ (MMBSDR) sediment delivery to rivers. For individual (n = 4485) non-coastal water bodies, the sediment ‘gap’ in excess of TMBSDR and MMBSDR, due to current land cover, cropping and stocking, was estimated to range up to 1368 kg ha⁻¹ yr⁻¹ (median 61 kg ha⁻¹ yr⁻¹) and 1321 kg ha⁻¹ yr⁻¹ (median 19 kg ha⁻¹ yr⁻¹), respectively. The respective ranges in conjunction with current land cover, cropping and stocking but corrected for the potential impact of on-farm sediment mitigation measures were up to 1315 kg ha⁻¹ yr⁻¹ (median 50 kg ha⁻¹ yr⁻¹) and 1269 kg ha⁻¹ yr⁻¹ (median 8 kg ha⁻¹ yr⁻¹). Multiplication of the estimates of excess sediment loss corrected for current measure uptake, above TMBSDR and MMBSDR, with estimated maximum unit damage costs for the detrimental impacts of sediment pollution on ecosystem goods and services, suggested respective water body ranges up to 495 £ ha⁻¹ yr⁻¹ and 478 £ ha⁻¹ yr⁻¹. Nationally, the total loss of sediment in excess of TMBSDR was estimated at 1,389,818 t yr⁻¹ equating to maximum environmental damage costs of £523 M yr⁻¹, due to current structural land use, compared to 1,225,440 t yr⁻¹ equating to maximum damage costs of £462 M yr⁻¹ due the uptake of on-farm sediment control measures. The corresponding total loss of sediment in excess of MMBSDR was estimated at 1,038,764 t yr⁻¹ equating to maximum damage costs of £462 M yr⁻¹, compared with 890,146 t yr⁻¹ and £335 M yr⁻¹ correcting excess agricultural sediment loss for current implementation of abatement measures supported by policy instruments. This work suggests that the current uptake of sediment control measures on farms across England and Wales is delivering limited benefits in terms of reducing loadings to rivers and associated environmental damage costs.     

‘Formiguers’, a historical system of soil fertilization (and biochar production?)

‘Formiguers’ are structures similar to charcoal-kilns that were used to burn piles of biomass with a soil cover in order to produce fertilizers for agricultural plots. Their use was widespread in Spain up to the 1960s and similar structures are still in use in India and Bhutan. Our objective was to study the effects of the ‘formiguer’ on its soil cover in terms of changes in nutrient availability. We built an experimental 0.5-m³ ‘formiguer’ with 68 kg of plant material with a 12% moisture content and 550 kg of soil with a 16% moisture content. The content of organic carbon and mineral nitrogen decreased in the soil cover as a result of burning. After aerobic incubation all samples had a similar content of mineral nitrogen. Exchangeable potassium and total and labile phosphorus increased after burning as a result of the soil cover mixing with the ashes of the biomass as the ‘formiguer’ collapsed during burning in the first two cases, while mineralization of organic compounds produced the increase in labile phosphorus. This input of nutrients for the agricultural plots occurs at a net loss of 0.4–2.5 Mg organic C ha^?1. Very small amounts of charcoal were produced and this may be the reason for their low occurrence in soils today. Burning of ‘formiguers’ required the harvest of vegetation from a considerable forest area (10–25 ha per hectare of agricultural land) and represented a significant disturbance of these systems.     

The role of indicator choice in quantifying the threat of atmospheric ammonia to the ‘Natura 2000’ network

New ‘critical levels’ (CLE) for assessing the effects of atmospheric ammonia on sensitive ecosystems have recently been adopted by the United Nations Economic Commission for Europe (UNECE) of 1 and 3 [2–4] μg NH₃ m^?3 of ambient air (including water vapour), for different species sensitivities and their associated habitats. Based on these values, we examined how indicator choice affects estimates of stock-at-risk in the European ‘Natura 2000’ network.We applied an atmospheric model, FRAME, to estimate surface air concentrations of ammonia at 5 km and 1 km resolution for the UK network of Natura sites, optionally including calibration with the National Ammonia Monitoring Network. As a base indicator, we estimated the overall percentage area of the UK Natura network that exceeded critical level thresholds (‘Area Weighted Indicator’, AWI). We compared this with an alternative approach, estimating the percentage number of Natura sites where the critical level was exceeded (‘Designation Weighted Indicator’, DWI), which we consider more relevant under the terms of the Habitats Directive.Using the AWI (with 1 km calibrated ammonia), we estimate that 11.2%, 1.3% and 0.2% area of the UK Natura network exceeds the critical level values of 1, 2 and 3 μg NH₃ m^?3, respectively. By contrast, using the DWI, the equivalent exceedances are 59.1%, 23.6% and 9.8%. The highest regional exceedance (DWI, critical level 1 μg NH₃ m^?3) was calculated for England (91.9% exceeded), and the lowest for Scotland (24.0% exceeded). High resolution maps show that the larger threat estimated by the DWI approach is explained by (i) an anti-correlation between NH₃ concentration and Natura site area and (ii) the fact that exceedance over part of a Natura site is considered to represent a threat to the integrity of the whole site.     

Comparison of mechanical properties of pure copper welded using friction stir welding and tungsten inert gas welding

The objective of this research is to investigate the mechanical properties including bonding, tensile strength, and impact resistance of pure copper welded using friction stir welding (FSW) method and compare them with that of tungsten inert gas (TIG) welding. Micro-hardness tests are performed on pure copper, TIG welded copper and FSW welded copper to determine the effect of heat on the hardness of welded coppers. Tensile strength tests and notch tensile strength tests are performed to determine the mechanical properties of different weld process.In this experiment, it is found that the notch tensile strength and the notch strength ratio for FSW (212 MPa, 1.10) are significantly higher than those (190 MPa, 1.02) of TIG welding. For the impact tests, the weld zone and heat-affected zone energy absorption values for FSW (2.87 J, 2.25 J) are higher than those (1.32 J, 0 J) of TIG welding. XRD tests are performed to determine components of copper before and after welding process for TIG and FSW.     

Streamwater phosphorus and nitrogen across a gradient in rural–agricultural land use intensity

This paper provides an overview of the impacts of rural land use on lowland streamwater phosphorus (P) and nitrogen (N) concentrations and P loads and sources in lowland streams. Based on weekly water quality monitoring, the impacts of agriculture on streamwater P and N hydrochemistry were examined along a gradient of rural–agricultural land use, by monitoring three sets of ‘paired’ (near-adjacent) rural headwater streams, draining catchments which are representative of the major geology, soil types and rural/agricultural land use types of large areas of lowland Britain. The magnitude and timing of P and N inputs were assessed and the load apportionment model (LAM) was applied to quantify ‘continuous’ (point) source and ‘flow-dependent’ (diffuse) source contributions of P to these headwater streams. The results show that intensive arable farming had only a comparatively small impact on streamwater total phosphorus (TP loads), with highly consistent stream diffuse-source TP yields of ca. 0.5 kg-P ha^?1 year^?1 for the predominantly arable catchments with both clay and loam soils, compared with 0.4 kg-P ha^?1 year^?1 for low agricultural intensity grassland/woodland on similar soil types. In contrast, intensive livestock farming on heavy clay soils resulted in dramatically higher stream diffuse-source TP yields of 2 kg-P ha^?1 year^?1. The streamwater hydrochemistry of the livestock-dominated catchment was characterised by high concentrations of organic P, C and N fractions, associated with manure and slurry sources. Across the study sites, the impacts of human settlement were clearly identifiable with effluent inputs from septic tanks and sewage treatment works resulting in large-scale increases in soluble reactive phosphorus (SRP) loads and concentrations. At sites heavily impacted by rural settlements, SRP concentrations under baseflow conditions reached several hundred μg-P L^?1. Load apportionment modelling demonstrated significant ‘point-source’ P inputs to the streams even where there were no sewage treatment works within the upstream catchment. This indicates that, even in sparsely populated rural headwater catchments, small settlements and even isolated groups of houses are sufficient to cause significant nutrient pollution and that septic tank systems serving these rural communities are actually operating as multiple point sources, rather than a diffuse input.     

Hermetic joining of 316L stainless steel using a patterned nickel nanoparticle interlayer

This paper evaluates the use of a nickel nanoparticle (NiNP) interlayer for making hermetic joints in 316L stainless steel substrates via diffusion brazing. Different NiNP inks were prepared using commercial nanopowder (～9 nm) and in-house synthesized nanoparticles. Syringe pump deposition of ～9 nm NiNP ink and diffusion brazing at 900 °C for 30 min under 2 MPa resulted in a hermetic joint up to the tested pressure of 70 psi. In-house synthesis of NiNPs was carried out in ethylene glycol by the reduction of NiCl₂·6H₂O in the presence of hydrazine (N₂H₄) as a reducing agent. X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM) results confirm the presence of pure fcc-Ni with an average particle size of 5.4 ± 0.9 nm. An as-synthesized suspension of NiNPs was patterned onto 316L stainless steel laminae via automated dispensing to a thickness of ～3 μm and bonded at 800 °C for 30 min at a pressure of 2 MPa. The diffusion-brazed test article was also found to be hermetic up to 70 psi. An examination of the bond line using scanning electron microscopy (SEM) showed good uniformity and continuity.     

Double-electrode arc welding process: Principle,variants, control and developments

Double-electrode gas metal arc welding (DE-GMAW) is a novel welding process in which a second electrode, non-consumable or consumable, is added to bypass part of the wire current. The bypass current reduces the heat input in non-consumable DE-GMAW or increases the deposition rate in consumable DE-GMAW. The fixed correlation of the heat input with the deposition in conventional GMAW and its variants is thus changed and becomes controllable. At the University of Kentucky, DE-GMAW has been tested/developed by adding a plasma arc welding torch, a GTAW (gas tungsten arc welding) torch, a pair of GTAW torches, and a GMAW torch. Steels and aluminum alloys are welded and the system is powered by one or multiple power supplies with appropriate control methods. The metal transfer has been studied at the University of Kentucky and Shandong University resulting in the desirable spray transfer be obtained with less than 100 A base current for 1.2 mm diameter steel wire. At Lanzhou University of Technology, pulsed DE-GMAW has been successfully developed to join aluminum/magnesium to steel. At the Adaptive Intelligent Systems LLC, DE-GMAW principle has been applied to the submerged arc welding (SAW) and the embedded control systems needed for industrial applications have been developed. The DE-SAW resulted in 1/3 reduction in heat input for a shipbuilding application and the weld penetration depth was successfully feedback controlled. In addition, the bypass concept is extended to the GTAW resulting in the arcing-wire GTAW which adds a second arc established between the tungsten and filler to the existing gas tungsten arc. The DE-GMAW is extended to double-electrode arc welding (DE-AW) where the main electrode may not necessarily to be consumable. Recently, the Beijing University of Technology systematically studied the metal transfer in the arcing-wire GTAW and found that the desired metal transfer modes may always be obtained from the given wire feed speed by adjusting the wire current and wire position/orientation appropriately. A variety of DE-AW processes are thus available to suit for different applications, using existing arc welding equipment.     

The precautionary principle and environmental persistence: prioritizing the decision-making process

There is continuing activity among regulatory bodies to assess and prioritize chemicals used in commerce based on their potential to be persistent, bioaccumulative, and toxic (PBT). Reliable data needed to perform a PBT hazard or risk assessment, however, may not always be readily available. Consequently concern may arise regarding the potential for false positives and false negatives to be wrongly classified. In order to more effectively classify substances, adequate time is needed to acquire the necessary data to support the overall PBT assessment. Of particular interest is the question of whether or not restrictions on the use and manufacture of a substance can be delayed to allow time to conduct the necessary field and laboratory studies of a particular substance? To address this question it is demonstrated that chemical partitioning property and environmental persistence information can be effectively combined to provide guidance for regulatory priority setting. Specifically, it is argued that substances that have media specific half-life values that exceed the regulatory threshold value for persistence under the EU chemicals REACH program, for example, are more likely to have a ‘legacy’ associated with their use when the log K_OA > 8, and when they are emitted to air or soil. Thus, precautionary actions limiting the use and manufacture of the substance may be warranted. Whereas substances emitted to air with log K_OA < 6 and log K_AW > ?2 are less likely to have a ‘legacy’ associated with their use. Thus precautionary actions in the absence of data may not be warranted.     

Shared control of robotic friction stir welding in the presence of imperfect joint fit-up

In this paper a shared control strategy is presented that allows a skilled operator to identify irregularities that occur during robotic friction stir welding (FSW) and assist the robotic system in producing an appropriate response. Human operators are adept at identifying disturbances; however, the complexity of the friction stir welding process makes it difficult for the operator to respond. While examining the capabilities of shared control in friction stir welding, this paper focuses on responding to defects that are caused by a lack of workpiece material during butt welding, such as gaps. A compensation strategy is presented that combines the human operator's perceptual strengths with an automated procedure for adjustment of the process parameters (i.e. travel angle and plunge depth). Experiments comparing four control strategies are performed while welding 5083-H116 aluminum. Through our experiments we demonstrate that if the FSW control task is appropriately shared between the human operator and the computer control system, the weld quality (strength) can be improved (from 9 ksi to 31 ksi for a gap size of 2.5 mm) as compared with the nominal case in which no corrections are made.     

The Satoyama Index: A biodiversity indicator for agricultural landscapes

Agricultural development to meet rapidly growing demands for food and biofuel and the abandonment of traditional land use have had major impacts on biodiversity. Habitat diversity is one of the most important factors influencing biodiversity in agricultural landscapes. In this study we propose an ecological index of ecosystem or habitat diversity in agricultural landscapes – the Satoyama Index (SI) – that is discernible under appropriate spatial units (e.g., 6 km × 6 km) from 1 km × 1 km gridded land-cover data available from an open-access web site. A high SI value is an indicator of high habitat diversity, which is characteristic of traditional agricultural systems, including Japanese satoyama landscapes, while a low value indicates a monotonic habitat condition typical of extensive monoculture landscapes. The index correlated well with the spatial patterns of occurrence of a bird of prey (Butastur indicus) and species richness of amphibians and damselflies in Japan. The values of the SI also corresponded well to the spatial patterns of typical traditional agricultural landscapes with high conservation value in other countries, for example, the dehesas of the Iberian Peninsula and shade coffee landscapes in Central America. Globally, the pattern of East/South-East Asian paddy belts with their high index values contrasts markedly with the low values of the Eurasian, American, and Australian wheat or corn belts. The SI, which correlates landscapes with biodiversity through potential habitat availability, is highly promising for assessing and monitoring the status of biodiversity irrespective of scale.     

Assessing the likelihood of catchments across England and Wales meeting ‘good ecological status’ due to sediment contributions from agricultural sources

This paper is concerned with estimating the gap between current and compliant losses of suspended sediment from the agricultural sector in England and Wales in relation to achieving ‘good ecological status’ (GES) in freshwaters by 2015. Given the emphasis on strategic information for policy support, the assessment necessitated a novel modelling methodology for predicting mean annual total suspended sediment loads (SSL) and time-weighted suspended sediment concentrations (SSC). GES was defined as the guideline annual average SSC of 25 mg l⁻¹ cited by the EC Freshwater Fish Directive. Total suspended sediment inputs to all rivers across England and Wales were estimated using a national sediment source apportionment exercise detailing the contributions from diffuse agricultural and urban sources, eroding channel banks and point sources. The total SSL estimated for each Water Framework Directive (WFD) sub-catchment (n = 7816) across England and Wales was used in conjunction with predicted flow exceedance to derive corresponding SSC time-exceedance plots. Spatial variations in modelled time-averaged SSC compared well with available monitoring data. Given the focus upon national scale, the predictive power of the SSC model (r² = 33%) was considered realistic. The modelling approach provided a means of mapping the probability of annual average SSC being less than the 25 mg l⁻¹ standard for GES due to sediment losses from all potential, as well as from agricultural sources only. In order to meet GES in non-compliant catchments, suspended sediment losses from diffuse agricultural sources will typically need to be reduced by up to 20%, but by as much as 80% in isolated cases.     

Ammonia and nitrous oxide emissions following land application of high and low nitrogen pig manures to winter wheat at three growth stages

Nitrous oxide (N₂O) and ammonia (NH₃) emissions from surface applied high (HN) and low (LN) nitrogen pig manures were measured under field conditions. Manures were band-spread to a winter wheat crop at three growth stages—mid-tillering, stem elongation and flag leaf emergence. The N₂O flux rates were measured using the static chamber technique while NH₃ volatilisation was assessed using a micrometeorological mass balance technique with passive flux samplers. The N₂O emissions were episodic in nature with flux rates observed ranging from 2.8 to 31.5 g N₂O–N ha^?1 day^?1 (P < 0.001). Higher N₂O emissions generally occurred after rainfall events. Highest N₂O losses were observed from the HN treatment with LN manure use decreasing emissions by 18% (P < 0.03). The NH₃ volatilisation rates were highest within 1 h of manure application with 95% of emissions occurring within 24 h (P < 0.001). Cumulative N loss was highest at mid-tillering as low crop canopy cover and increased wind-speeds enhanced NH₃ loss (P < 0.001). Highest emissions were measured from the HN manure (P < 0.03). Total ammoniacal N loss ranged from 6 to 11%. Crop N uptake and grain yield were unaffected by application timing or manure type. Therefore, the use of LN manures decreased gaseous emissions of N₂O and NH₃ without any adverse effects on crop performance.     

Innovative cleaner production for steel phosphorization using Zn–Mn phosphating solution

Phosphating prior to coating for steel is usually needed. In this paper, an innovative cleaner production has been developed for steel surface treatment using Zn–Mn phosphating solution in which there was no nitrite. The mass of the Zn–Mn layer deposited in this new process was about 1.1 g m^?2 when the temperature ranged from 3 to 35 °C. The corrosion time for the color phosphating layer in the copper sulfate spot test was in the range of 72–145 s. Adhesion test showed that the coating layers achieved a higher adhesion load than those produced by conventional methods. Washing using water was not necessary in this cleaner phosphorization, which usually follows phosphorization in traditional processes of steel phosphorization. Consequently, wastewater discharge was reduced greatly.     

Environmental consequences of different beef production systems in the EU

The aim of this paper is to examine the environmental consequences of beef meat production in the EU, using a life cycle approach. Four beef production systems were studied – three from intensively reared dairy calves and one from suckler herds. According to the results of the analysis, the contributions from the production of 1 kg beef meat (slaughter weight) to global warming, acidification, eutrophication, land use and non-renewable energy use were lower for beef from dairy calves than from suckler herds (16.0–19.9 versus 27.3 kg CO₂e, 101–173 versus 210 g SO₂e, 622–1140 versus 1651 g NO₃e, 16.5–22.7 versus 42.9 m²year, and 41.3–48.2 versus 59.2 MJ, respectively). The breakdown analysis helped identify the key areas in the “cradle to farm gate” beef production system where sustainable management strategies are needed to improve environmental performance. The study also included a sensitivity analysis to preliminarily estimate GHG emissions from beef production systems if land opportunity cost and land use change related to grazing and feed crop production for beef were taken into account. If so, the contribution from the production of 1 kg beef to global warming would increase by a factor of 3.1–3.9, based on a depreciation period of 20 years. This highlights the importance of taking into account the impacts of land use in assessing the environmental impacts of livestock production.     

Emissions of N2O and NH3, and nitrogen leaching from direct seeded rice under different tillage practices in central China

Tillage practices affect the fate of fertilizer nitrogen (N) through influencing transformations of N, but few studies have examined N₂O and NH₃ emissions, and N leaching from different rice tillage systems. Thus the objective of this study was to assess N₂O emission, NH₃ volatilization and N leaching from direct seeded rice in conventional tillage (CT) and no-tillage (NT) production systems in the subtropical region of China during the 2008 and 2009 rice growing seasons. Treatments were established following a split-plot design of a randomized complete block with tillage practices as the main plot and N fertilizer level as the sub-plot treatment, and there were four treatments: NT + no fertilizer (NT0), CT + no fertilizer (CT0), NT + compound fertilizer (NTC) and CT + compound fertilizer (CTC), respectively. Results showed that N fertilization significantly increased (p < 0.01) N₂O emissions, NH₃ volatilization and N leaching from rice fields in both years. In general, there was no significant difference in N₂O emissions and NH₃ volatilization between NT0 and CT0 in both years, while NTC had significantly higher (p < 0.05) N₂O emissions and NH₃ volatilization compared to CTC. Over the two rice growing seasons, NTC showed 32% and 47% higher N₂O emissions, and 29% and 52% higher NH₃ losses than CTC. Higher (p < 0.05) N₂O emissions from NTC than CTC were presumably due to higher soil organic C and greater denitrification. Total N and NO₃^? concentrations were higher (p < 0.05) in CTC than NTC, but larger volumes of percolation water in NTC than CTC resulted in no significant difference in leakage of total N and NO₃^?. Hence, application of N fertilizer in combination with NT appeared to be ineffective in reducing N losses from N fertilizer in paddy fields.