Total and extractable element concentrations in bed sand material from a medium-sized (32 MW) municipal district heating plant incinerating peat, stumps, sawdust and recycled wood

In Finland, the new limit values of total heavy metal, polychlorinated biphenyl (PCB) and polycyclic aromatic hydrocarbon (PAH), as well as the extractable heavy metal, dissolved organic carbon (DOC), fluoride, sulphate, and chloride concentrations for bed sand material used as an earth construction agent came into force in June 2009. The total heavy metal (i.e. Cd, Cu, Pb, Cr, Zn, As, V, Ba and Mo) concentrations in the studied bed sand material were clearly lower than the current Finnish limit values for the maximum allowable heavy metal concentrations for materials used as an earth construction agent. However, the extractable concentration of Ba (24.6 mg kg⁻¹; d.w.) in the bed sand material exceeded the limit value for covered structures (20 mg kg⁻¹; d.w.). However, in Finland, the competent environmental authority may relax the maximum limit values up to 30% in certain circumstances. Therefore, if, the environmental authority relaxes the maximum limit value for the extractable concentration of Ba by up to 30% to the value of 26 mg kg⁻¹ (d.w.) for covered structures, the extractable concentration of Ba (24.6 mg kg⁻¹; d.w.) in the bed sand material is below this relaxation.     

Effect of Residual Stress and Strain-Induced α′-Martensite on Delayed Cracking of Metastable Austenitic Stainless Steels

The role of residual stresses and strain-induced α′-martensite in delayed cracking of metastable austenitic stainless steels was studied by means of Swift cup tests, measurement of residual stresses by X-ray diffraction and ring slitting, and α′-martensite content determination. Low-Ni, high-Mn austenitic stainless steels, e.g., AISI 201, were compared with Fe-Cr-Ni austenitic stainless steels. The presence of α′-martensite seemed to be a necessary prerequisite for delayed cracking to occur in austenitic stainless steels with typical internal hydrogen concentrations (<5 ppm). Stable low-Ni austenitic stainless steel was not prone to delayed cracking. The low-Ni metastable grades showed more severe cracking at lower degree of deformation and lower volume fraction of α′-martensite than that of the metastable 300-series grades. The limiting α′-martensite content, below which delayed cracking did not occur, decreased along with the nickel content of the material. The strain-induced martensitic transformation substantially increased the magnitude of residual stresses in deep-drawn cups. One explanation for high sensitivity of the low-Ni grades to delayed cracking after deep drawing is their higher residual stresses compared to that of the Fe-Cr-Ni grades. Alloying elements of the stainless steels, nickel, and carbon in particular, influence the sensitivity to delayed cracking through their effect on the properties of the α′-martensite.     

Partial Virtual Channel Sharing: A Generic Methodology to Enhance Resource Management and Fault Tolerance in Networks-on-Chip

We present a novel Partial Virtual channel Sharing (PVS) NoC architecture which reduces the impact of faults on performance and also tolerates faults within the routing logic. Without PVS, failure of a component impairs the fault-free connected components, which leads to considerable performance degradation. Improving resource utilization is key in enhancing or sustaining performance with minimal overhead when faults or overload occurs. In the proposed architecture, autonomic virtual-channel buffer sharing is implemented with a novel algorithm that determines the sharing of buffers among a set of ports. The runtime allocation of the buffers depends on incoming load and fault occurrence. In addition, we propose an efficient technique for maintaining the accessibility of a processing element (PE) to the network even if its router is faulty. Our techniques can be used in any NoC topology and for both, 2D and 3D NoCs. The synthesis results for an integrated video conference application demonstrate 22 % reduction in average packet latency compared to state-of-the-art virtual channel (VC) based NoC architecture. Extensive quantitative simulation has been carried out with synthetic benchmarks. Simulation results reveal that the PVS architecture improves the performance significantly in presence of faults, compared to other VC-based NoC architectures.     

Sorption of Pb(II), Cr(III), Cu(II), As(III) to peat,and utilization of the sorption properties in industrial waste landfill hydraulic barrier layers

The low conductivity landfill barrier layers protect the groundwater and soil by limiting the water flow through the bottom layers of the landfill material. Many materials used in hydraulic barrier layers also have sorption properties which could be used to reduce environmental risks. The adsorption of lead, chromium, copper, and arsenic to peat was studied with a batch-type test and a column test for compacted peat, both without pH adjustment in acidic conditions. Peat adsorbed all the metals well, 40 000 mg/kg of lead, 13 000 mg/kg of chromium, and 8400 mg/kg of copper in the column test. Arsenic was only tested in a batch-type test, and in that peat adsorbed 60 mg/kg of arsenic. The column test showed heavy metals to be adsorbed on the surface layers of the compacted peat sample, on the first centimeter of the sample. The adsorption was much greater in the column test than in the batch-type test, partly due to the different pH conditions and the buffer capacity of the peat in the column test. The liquid/solid ratio of the column experiment represented a time period of approximately 40 years in a landfill, under Finnish climate conditions. The hydraulic conductivity of the peat decreased as it was compressed, but it already met the hydraulic conductivity limits set by European Union legislation for the hydraulic barrier layer (1 × 10⁻⁹ m/s at a pressure of 150 kPa for a 5-m layer), with a pressure of 50 kPa. The results show that peat would be an excellent material to construct compacted, low hydraulic conductivity layers with adsorption properties in, e.g. industrial waste landfills.     

Compensatory fertilization of Scots pine stands polluted by heavy metals

The results from four compensatory fertilization experiments located at different distances (0.5, 2, 4 and 8 km) along a heavy metal deposition gradient extending from the Harjavalta Cu-Ni smelter in SW Finland are presented. The experiments were established in middle-age Scots pine stands growing on dryish sites of sorted glaciofluvial sediments. The soil type in all the experiments is ferric podsol. The treatments in the experiments consisted of liming, a powdered slow-release mineral mixture and stand-specific fertilization which comprised at least methylene urea and ammonium nitrate.Monitoring of deposition and soil solution and studies on soil chemical and microbiological properties, on the nutrient status of trees and needle litterfall, on fine root dynamics and on the growth of the tree stands were carried out during a 5-year period.There was a severe shortage of exchangeable Ca and Mg in the organic layer of the most polluted stands. Although the uppermost mineral soil layer had relatively high exchangeable Ca and Mg concentrations, the trees were not able to utilize these nutrient reserves presumably due to the toxic effects of Cu and Ni on the plant roots and mycorrhizas.The treatments that included limestone markedly decreased the Cu and Ni concentrations in the soil solution and soil organic layer, presumably due to immobilisation through precipitation or absorption. The Ca and Mg concentrations correspondingly increased, which certainly contributed to the partial recovery of fine root and stand growth. The powdered mineral mixture and the combination of methylene urea and ammonium nitrate had no short-term effect on the microbial biomass and activity. All the fertilizer treatments increased volume growth in the most polluted stand. The stand-specific fertilization increased needle mass in heavily polluted stands, but the response of the needle mass to fertilizer treatments was low in the less polluted stands. No clear evidence was found to support the role of nutrient status in tree resistance.     

The State and Self-help Housing in Urban Finland, 1920 to 1950

This paper examines self-help housing and state housing policies in urban Finland from 1920 to 1950. In Finland self-help housing consisted primarily of self-building of one- and two-family houses. It is often assumed that self-building used to be the typical urban form of housing production. It was certainly the form that housing reformers preferred. However, most urban housing production was private speculative production. Self-building became relatively important only when other production was depressed. The state supported self-building by providing subsidised housing finance. Of the three successive housing finance systems examined, only the last concerned only self-building. The loan policies also included an attempt to control the quality and design of self-built housing. The policies were, however, so limited that they did not have a large impact on urban housing in normal times. In Finland, as in many other countries, the government's attitude towards self-building can be characterised as guarded support.     

Characterisation of Fractions Obtained by Isoamylolysis and Ion‐exchange Chromatography of Cationic Waxy Maize Starch

Isoamylase hydrolysates of wet‐ (WC) and dry‐cationised (DC) waxy maize starch were fractionated by ion‐exchange chromatography on CM‐Sepharose into an unbound and four bound fractions. The amount of bound dextrins was higher in the WC than in the DC sample. The fractions were characterised by gel‐permeation chromatography and proton‐NMR spectroscopy. The unbound fraction from the WC sample consisted mainly of linear chains formed from amylopectin. The dextrins in the bound fractions contained increased amounts, from 1.2—7.9, of cationic substituents per molecule and the degree of polymerisation increased with the density of substituents. Dextrins weakly bound to CM‐Sepharose had a linear structure, whereas more tightly bound fractions were mixtures of linear and branched dextrins. In the latter, the debranching was incomplete because of sterical hindrance by substituents at or close to the branch points. Most of the dextrins were partly hydrolysed by β‐amylase, but the more highly substituted fractions possessed also a population of β‐amylase resistant dextrins, suggesting substituents at the non‐reducing ends.     

KLK3 in the Regulation of Angiogenesis—Tumorigenic or Not?

In this focused review, we address the role of the kallikrein-related peptidase 3 (KLK3), also known as prostate-specific antigen (PSA), in the regulation of angiogenesis. Early studies suggest that KLK3 is able to inhibit angiogenic processes, which is most likely dependent on its proteolytic activity. However, more recent evidence suggests that KLK3 may also have an opposite role, mediated by the ability of KLK3 to activate the (lymph)angiogenic vascular endothelial growth factors VEGF-C and VEGF-D, further discussed in the review.     

Bringing back ecological flows: migratory fish,hydropower and legal maladaptivity in the governance of Finnish rivers

ABSTRACT

Historically, Finnish rivers supported vital populations of migratory salmonids. Presently, these species are more or less endangered due to extensive damming and hydropower production. In this article, we study the main legal and scientific drivers for re-evaluating some of the existing hydropower operations in Finland. We argue that there is a need for re-evaluation on the basis of legal obligations stemming largely from EU law and new scientific knowledge. Theoretically, our setting opens up a classical adaptive governance problem in how to address laws and past decisions that are based on outdated assumptions about the functioning of social-ecological systems.