Reasons For Different Performances Research Articles

Assessing the multidimensional elements of sustainability in European agroforestry systems

CONTEXTAgroforestry is gaining interest in in Europe however the trade-offs associated with its uptake are still uncertain. OBJECTIVEThe objective of this study was to explore the sustainability trade-offs and synergies associated with a range of agroforestry systems in Europe and assess the underlying reasons for different performance regarding environmental, economic, social and governance domains. METHODSFive case-studies of agroforestry from nothern, eastern and southern Europe were assessed using an established sustainability assessment tool, the Public Goods tool (PG tool). The case studies were selected to represent a range of innovative and traditional systems, encompassing arable and livestock, wood fuel and tree fruit crops. RESULTS AND CONCLUSIONSAll five of the case studies were performing well across a diverse range of sustainability criteria, with average scores of three out of five or higher across the assessment categories. Social capital and animal health and welfare management scores were particularly high, due to high rates of on-farm employment of between 0.4 and 2.3 full-time labour units per hectare, and a high volume of local sales alongside effective health planning and husbandry through health planning and a lack of restrictions on natural behaviour. Land Equivalent Ratios were greater than 1 within each case and were particularly high for established silvopasture systems (over 1.5). Fossil fuel use was considerably lower than the industry average in most of the case studies (between 17 and 92% of the country-average per hectare for three of the cases). Economic performance was highly variable, with high labour costs contributing to negative margins. SIGNIFICANCEThe assessments show that agroforestry systems have considerable potential to contribute to multiple sustainability objectives, and that environmental and social sustainability objectives are particularly well addressed through increased efficiency of land-use, increased opportunities for on-farm employment and engagement with local communities. However considerable financial barriers still exist and may prevent its further uptake. Promoting the future uptake of agroforestry in Europe therefore requires the commitment of multiple actors in supply chains to plan policies, farm-practices and knowledge exchange that can support the delivery of sustainability benefits.

Influence of pH on short-cut denitrifying phosphorus removal

Through a series of experiments using denitrifying phosphorus-accumulating sludge in sequencing batch reactors (SBRs), the variations of the intracellular polymers during the anaerobic phosphorus release process at different pH values were compared, the probable reasons for different performances of phosphorus removal were examined, and system operations in a typical cycle were investigated. The results show that the phosphorus removal rate was positively correlated with pH values in a range of 6.5–8.5. When the pH value was 8.0, the anaerobic phosphorus release rate and anoxic phosphorus uptake rate of the activated sludge were 20.95 mg/(g∙h) and 23.29 mg/(g∙h), respectively; the mass fraction of poly-β-hydroxybutyrate (PHB) increased to 62.87 mg/g under anaerobic conditions; the mass fraction of polyphosphate was 92.67 mg/g under anoxic conditions; and the effluent concentration of total phosphorus (TP) was 1.47 mg/L. With the increase of pH, the mass fraction of acetic acid and PHB also increased, and the absorption rate of acetic acid was equal to the disintegration rate of polyphosphate. When the pH value was above 8.0, biological phosphorus removal was achieved by chemical phosphorus precipitation, and the phosphorus removal rate decreased.

Low temperature SCR of NO with catalysts prepared by modified ACF loading Mn and Ce: effects of modification method

Achievement of a higher NOx conversion ratio in selective catalytic reduction (SCR) at low temperature is challenging. In this work, pure activated carbon fibres (ACFs) were modified with different ratios of H2O (g), NaOH, CO2 and HNO3, respectively (named as modified ACF). The chemical and physical properties of modified ACFs were identified by Brunauer–Emmett–Teller, X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy methods. The NOx conversion ratio of ACF was improved from 56.1% to 82.4% at 80°C after modification with 30% (mass ratio) NaOH. These modified ACFs were further loaded with the mixture of MnO2 and CeO2 in the form of metal salt solutions (named as Mn0.5Ce0.5O2/modified ACF). The NOx conversion ratio of 30% SHACF remained similar at 80°C but was increased from 60.0% to 98.5% at 360°C after loading with Mn and Ce, which showed the best performance in SCR of NOx at low temperature. It could be seen that ACF delivered higher performance in low temperature SCR after being modified with the aforementioned reactants and further loading with metals. Based on chemical and physical characterization and the performance of the catalysts, the reasons for different performances of these catalysts in low temperature SCR are discussed.

Configuration and performance analysis of magnetic refrigerators

The commercialization of magnetic refrigerators depends upon the ability to meet performance targets while having acceptable equipment costs. This paper links device design parameters and performance of magnetic refrigerators to the cost of cooling delivered. A device configuration parameter, D, is defined that links the field volume to the volume of magnetocaloric material. Combined with the magnet performance parameter, efficiency, and specific exergetic cooling, the cost structure of a magnetic refrigerator is determined. Some magnetic refrigerators reported in the literature are classified using their configuration parameters, and are then compared in terms of demonstrated performance using results available in the literature. The required improvement in performance is calculated such that the cost of a magnetic refrigerator would be equivalent to a conventional compressor-based device. Finally, some of the reasons for different performance are discussed with a focus on opportunities for improvements.

Investigating thickness and internal structure of alpine mires using conventional and geophysical techniques

article i nfo We investigated the thickness and composition of five small alpine mires in Tyrol (Austria), performing a combination of conventional techniques (telescope rods, drilling) and geophysical methods. GPR surveys were carried out using 100 and 200 MHz antennas. Geoelectrical profiles supplemented the GPR at two sites; the 2D-surveys were enhanced by additional 1D-profiling. The aim was to achieve data on mire thickness, to cross-check the methods and to find reasons for different performance at the five sites. The investigations contribute to establishing a future protection concept. The formation history of the mires probably goes back to the early Holocene. The three larger mires are terrestrialisation mires, while two mires are formed by paludification. Probing with a metal rod was subject to considerable errors in both directions caused by obstacles and soft underlying layers. Thus, GPR proved to be a favourable addition to conventional depth assessment. At four of five sites, GPR made it possible to depict the base layer of the mires at a high accuracy, while detecting peat internal interfaces was less successful. 2D-resistivity profiling supplemented with 1D-modelling provided excellent additional informa- tion on mire base and deeper subsurface; at one site where minerogenic material is washed in, 2D-resistivity proved to be the better choice compared to GPR.