Carbon loss estimates from cultivated peat soils in Norway: a comparison of three methods

Drainage and cultivation of peat soils stimulates soil organic matter (SOM) mineralization, which substantially increases CO₂ emissions from soils. Large uncertainties are associated with this CO₂ flux, and little data are available, especially in Norway. The objective of the present research was to estimate C losses from cultivated peatlands in West Norway by three independent methods: (1) long-term monitoring of subsidence rates, (2) changes in ash contents, and (3) soil CO₂ flux measurements. Subsidence of cultivated peat soils averaged about 2.5 cm year⁻¹. We estimated that peat loss and compaction were respectively responsible for 38% and 62% of the total subsidence during a 25-year period after drainage. Based on this estimate the corresponding C loss equals 0.80 kg C m⁻² year⁻¹. The observed increase in mineral concentration of the topsoil of cultivated peat is proportional to their C loss, providing no mineral particles other than lime and fertilizers are added to the soil. Using this novel approach across 11 sites, we estimated a mean C loss of 0.86 kg C m⁻² year⁻¹. Soil CO₂ flux measurements, corrected for autotrophic respiration, yielded a C loss estimate from cultivated peat soils of 0.60 kg C m⁻² year⁻¹. The three methods yielded fairly similar estimates of C losses from Norwegian cultivated peatlands. Cultivated peatlands in Norway cover an estimated 63,000 ha. Total annual C losses from peat degradation were estimated to range between 1.8 and 2 million tons CO₂ year⁻¹, which equals about 3–4% of total anthropogenic greenhouse gas emissions from Norway.     

Statistically accurate length measurements of single-walled carbon nanotubes

The ability to accurately measure the length of nanotubes is important to understanding nanotube growth and cutting processes. To date, there have been few methods available to obtain a statistically significant length measurement of any nanotube sample due to difficulties in obtaining a complete suspension of individual nanotubes and the tedious nature of measuring 1000+ nanotubes. Here we describe a relatively simple method that functionalizes single-walled carbon nanotubes to achieve a high propensity of individual nanotubes in chloroform as high as 92%. This suspension can be dispersed on mica substrates for AFM analysis. Nanotube lengths and heights can be determined using the Nanotube Length Analysis module of SIMAGIS yielding an accurate measure of length and height distribution of a large population of the nanotube sample.     

DNA damage in Gammarus fossarum sperm as a biomarker of genotoxic pressure: intrinsic variability and reference level

In the perspective of a biomonitoring application for assessing genotoxicity of freshwater ecosystems, the Comet assay has recently been developed on spermatozoa in the amphipod Gammarus fossarum, in order to propose a sensitive and reliable genotoxicity biomarker in an ecologically relevant freshwater species. The appropriate use of a genotoxicity biomarker requires good knowledge of its basal level and its natural variability related to intrinsic biotic and environmental abiotic factors. We propose a procedure for which the lowest biomarker variability related to methodological and intrinsic biotic factors is obtained and a reference value of biomarker basal response taking into account its spatio-temporal changes has been defined. A strong impact of spermatogenesis status and exposure time on the response to genotoxicant pressure was observed. These reports led us to select a standard organism, i.e., the mature male gammarid in precopula. No effect of temperature and conductivity on baseline DNA damage was observed in the laboratory for the tested range (6-24 °C and 300/600 μS cm⁻¹). Similarly, no spatio-temporal change relative to season or the physico-chemical characteristics of the water was recorded during the field survey. On the basis of these results, a reference level with maximal threshold values has been proposed for the standard gammarid.     

User evaluation of the indoor climate of the first passive house school in Norway

The indoor climate of the first passive house school in Norway was evaluated with the aid of a questionnaire (Örebro) with approximately 340 respondents, and three interview rounds with a total of 23 informants. The intention was to reveal whether the users experienced any problems or possibly better conditions than in a regular school building. The interviews showed that, overall, the users were satisfied with the building. The survey showed generally good results for the indoor climate. Questionnaire results were compared with reference material consisting of data for average school buildings. The indoor climate of Marienlyst School was better than the average for most of the symptoms of indoor air quality problems, for both pupils and teachers. The users did still experience some problems with the building, relating to the fine-tuning of the automatic systems: temperature control, solar control, static electricity, and pressure conditions in the building. The users also said they lacked information about the passive house concept, the building, and how to obtain optimal functionality of the automatic control systems. The reasons for the fine-tuning problems are discussed in relation to the passive house concept, and the problem indicators are probably not attributable to the concept.     

Principles for assessment and diagnosis of work-related pulmonary and pleural diseases

Proposals for diagnostic methods and clinical evaluation of occupational lung and pleural diseases have been worked out by a Working Group appointed by the Norwegian Thoracic Society and the Norwegian Society of Occupational Medicine. The management of this group of diseases demands both an evaluation of occupational exposure and a specific pulmonary diagnosis. Recommendations were made especially for obstructive, interstitial, and malignant diseases.     

Synthesis of high aspect-ratio carbon nanotube "flying carpets" from nanostructured flake substrates

We present a robust method for synthesis of aligned, single-walled carbon nanotube (CNT) "flying carpets" from nanostructured alumina flakes. Roll-to-roll e-beam deposition is utilized to produce the flakes, and hot filament chemical vapor deposition is utilized to grow dense, aligned carbon nanotubes from the flakes with remarkably high CNT yields. The flakes are captured inside a mesh cage and freely suspended in the gas flow during growth. Optical characterization indicates the presence of high quality, small diameter single-walled carbon nanotubes.     

Crystallization and orientation studies in polypropylene/single wall carbon nanotube composite

Crystallization behavior of melt-blended polypropylene (PP)/single wall carbon nanotube (SWNT) composites has been studied using optical microscopy and differential scanning calorimetry. Polypropylene containing 0.8 wt% SWNT exhibits faster crystallization rate as compared to pure polypropylene. PP/SWNT fibers have been spun using typical polypropylene melt spinning conditions. The PP crystallite orientation and the SWNT alignment in the fibers have been studied using X-ray diffraction and polarized Raman spectroscopy, respectively.     

Optical quality of rotationally symmetrical contact lenses derived from their power profiles

Purpose

To present a methodology for evaluating the optical quality of rotationally symmetrical contact lenses (CLs) from a single power profile.