Models for predicting stand development in MELA System

This document addresses the models that are developed to be applicable in the simulation of stand development for forest management planning purposes. A detailed description is provided of the models predicting regeneration, growth and mortality, together with auxiliary models required for the simulation of stand development. Models were developed to be applicable for the all tree species and on all the forest site types throughout the Finland. The model input were restricted to those variables that are measurable in large-scale forest inventories. Extensive data from repeatedly measured inventory growth plots and permanent sample plots were used in the model development. Most of the models in the simulation system can be categorized as individual-tree, distance independent models. After model building they were evaluated and calibrated using the temporary sample plot data from the 8th National Forest Inventory. The purpose was to calibrate the predicted growth to the average level obtained from the growth measurements of national forest inventory, and obtain the growth predictions also for those tree species, and site types that were poorly represented in the modelling data

Vuosisadan rakennemuutos : väestö, talous ja tasa-arvo

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A miniaturised 3D printed polypropylene reactor for online reaction analysis by mass spectrometry

Correction: Reaction Chemistry & Engineering, vol. 2:5, p. 811 DOI: 81110.1039/C7RE90018JA miniaturised polypropylene reactor was fabricated by 3D printing using fused deposition modeling. A stainless steel nanoelectrospray ionisation capillary and a magnetic stir bar were integrated into the reactor during the printing process. The integrated nanoelectrospray ionisation capillary allows direct sampling of a reaction solution without external pumping. It also allows ionisation of the analytes. Therefore, very rapid online mass spectrometric chemical reaction monitoring is possible. Operation of the miniaturised reactor is shown by the online nanoelectrospray mass spectrometry characterisation of a Diels–Alder reaction and the subsequent retro Diels–Alder reaction.Peer reviewe

Validation of SMOS sea ice thickness retrieval in the northern Baltic Sea

The Soil Moisture and Ocean Salinity (SMOS) mission observes brightness temperatures at a low microwave frequency of 1.4 GHz (L-band) with a daily coverage of the polar regions. L-band radiometry has been shown to provide information on the thickness of thin sea ice. Here, we apply a new emission model that has previously been used to investigate the impact of snow on thick Arctic sea ice. The model has not yet been used to retrieve ice thickness. In contrast to previous SMOS ice thickness retrievals, the new model allows us to include a snow layer in the brightness temperature simulations. Using ice thickness estimations from satellite thermal imagery, we simulate brightness temperatures during the ice growth season 2011 in the northern Baltic Sea. In both the simulations and the SMOS observations, brightness temperatures increase by more than 20 K, most likely due to an increase of ice thickness. Only if we include the snow in the model, the absolute values of the simulations and the observations agree well (mean deviations below 3.5 K). In a second comparison, we use high-resolution measurements of total ice thickness (sum of ice and snow thickness) from an electromagnetic (EM) sounding system to simulate brightness temperatures for 12 circular areas. While the SMOS observations and the simulations that use the EM modal ice thickness are highly correlated (r2=0.95), the simulated brightness temperatures are on average 12 K higher than observed by SMOS. This would correspond to an 8-cm overestimation of the modal ice thickness by the SMOS retrieval. In contrast, if the simulations take into account the shape of the EM ice thickness distributions (r2=0.87), the mean deviation between simulated and observed brightness temperatures is below 0.1 K

Simple 3D printed stainless steel microreactors for online mass spectrometric analysis

A simple flow chemistry microreactor with an electrospray ionization tip for real time mass spectrometric reaction monitoring is introduced. The microreactor was fabricated by a laser-based additive manufacturing technique from acid-resistant stainless steel 316L. The functionality of the microreactor was investigated by using an inverse electron demand Diels-Alder and subsequent retro Diels-Alder reaction for testing. Challenges and problems encountered are discussed and improvements proposed. Adsorption of reagents to the rough stainless steel channel walls, short length of the reaction channel, and making a proper ESI tip present challenges, but the microreactor is potentially useful as a disposable device.Peer reviewe

Thin ice and storms: Sea ice deformation from buoy arrays deployed during N-ICE2015

Arctic sea ice has displayed significant thinning as well as an increase in drift speed in recent years. Taken together this suggests an associated rise in sea ice deformation rate. A winter and spring expedition to the sea ice covered region north of Svalbard – the Norwegian young sea ICE 2015 expedition (N-ICE2015) - gave an opportunity to deploy extensive buoy arrays and to monitor the deformation of the first- and second-year ice now common in the majority of the Arctic Basin. During the 5-month long expedition, the ice cover underwent several strong deformation events, including a powerful storm in early February that damaged the ice cover irreversibly. The values of total deformation measured during N-ICE2015 exceed previously measured values in the Arctic Basin at similar scales: At 100 km scale, N-ICE2015 values averaged above 0.1, day−1, compared to rates of 0.08 day −1 or less for previous buoy arrays. The exponent of the power law between the deformation length scale and total deformation developed over the season from 0.37 to 0.54 with an abrupt increase immediately after the early February storm, indicating a weakened ice cover with more free drift of the sea ice floes. Our results point to a general increase in deformation associated with the younger and thinner Arctic sea ice and to a potentially destructive role of winter storms

Investigation of thermal influence on weld microstructure and mechanical properties in wire and arc additive manufacturing of steels

Alloy steels are commonly used in many industrial and consumer products to take advantage of their strength, ductility, and toughness properties. In addition, their machinability and weldability performance make alloy steels suitable for a range of manufacturing operations. The advent of additive manufacturing technologies, such as wire and arc additive manufacturing (WAAM), has enabled welding of alloy steels into complex and customized near net-shape products. However, the functional reliability of as-built WAAM products is often uncertain due to a lack of understanding of the effects of process parameters on the material microstructure and mechanical properties that develop during welding, primarily driven by thermal phenomena. This study investigated the influence of thermal phenomena in WAAM on the microstructure and mechanical properties of two alloy steels (G4Si1, a mild steel, and AM70, a high-strength, low-alloy steel). The interrelationships between process parameters, heating and cooling cycles of the welded part, and the resultant microstructure and mechanical properties were characterized. The welded part experienced multiple reheating cycles, a consequence of the layer-by-layer manufacturing approach. Thus, high temperature gradients at the start of the weld formed fine grain structure, while coarser grains were formed as the height of the part increases and the temperature gradient decreased. Microstructural analysis identified the presence of acicular ferrite and equiaxed ferrite structures in G4Si1 welds, as well as a small volume fraction of pearlite along the ferrite grain boundaries. Analysis of AM70 welds found acicular ferrite, martensite, and bainite structures. Mechanical testing for both materials found that the hardness of the material decreased with the increase in the height of the welded part as a result of the decrease in the temperature gradient and cooling rate. In addition, higher hardness and yield strength, and lower elongation at failure was observed for parts printed using process parameters with lower energy input. The findings from this work can support automated process parameter tuning to control thermal phenomena during welding and, in turn, control the microstructure and mechanical properties of printed parts.publishedVersionPeer reviewe