Integrated supply of stemwood and residual biomass to forest-based biorefineries

The demand for forest biomass as raw material for a wide range of products in the developing bioeconomy is expected to increase. Along with a constant pressure on forestry to increase its productivity, this development has led to the search for new procurement methods and new assortments. The present study assessed innovative supply chain practices, with a particular focus on the integrated supply of stemwood and residual tree parts. The assortments considered included tree sections, long tops, saw logs with stump cores and small whole trees from thinnings. The assessment included geographically explicit modelling of the supply chain operations and estimation of supply cost and energy use for three industrial locations in Northern Sweden. The innovative supply chains were compared to conventional, separate, harvest of stemwood and logging residues. We conclude that integrated harvest of tops and branches with stemwood assortments, as well as whole-tree harvest in early thinnings, has a significant potential to reduce the supply cost for the non-stemwood assortments. Stump wood generally remains the most expensive assortment. The energy use analysis confirms earlier research showing that the energy input is relatively small compared to the energy content of the harvested feedstock

Fuel, Hydraulic Oil and Lubricant Consumption in Swedish Mechanized Harvesting Operations, 1996

When subjecting forest products to certification the total environmental load of wood harvesting machinery should also be assessed. In this study fuel, hydraulic oil and lubricant consumption in harvesting operations in Sweden has been examined by using machine data acquired through a questionnaire. The objectives of the study were to assess the contractor and forest company owned harvesters' and forwarders' average oil consumption in practical harvesting operations in Sweden, ascertain if the ownership and size of the machines give different consumption figures and estimate the use of environmentally acceptable hydraulic oils as well as the amount of oil spilled outdoors. Diesel consumption was found to be 935 l/1000 m3ub for forwarders and 1 167 l/1000 m3ub for single-grip harvesters. Hydraulic, transmission and chainsaw oil consumption was significantly higher in forest company owned harvesters while no significant differences were observed among forwarders. Hydraulic oil spillage was estimated for both harvesters and forwarders at 20 l/1000 m3ub. For felling and crosscutting trees a further 35 l/1000 m3ub of chainsaw oil is spilled. Ninety percent of the utilized hydraulic oil was environmentally compatible

Fuel Consumption In Forwarders

Forwarder fuel consumption was studied by examining a total of 27 forwarders under field conditions. Three datasets, representing different data acquisition methods, were used. In a field study, time and fuel consumption by work-element of two 20-21 tonne forwarders in final felling were recorded. In a questionnaire survey, daily data concerning fuel consumption, productivity and average extraction distance was provided on 18 forwarders, divided between final felling and thinning. Finally, accounting data on fuel consumption for 11 forwarders were obtained. In the field study, the fuel consumption varied between 8.3 to 15.7 l/PMH (productive machine hour) for different work elements. The total fuel consumption was 0.28-0.36 l/m3sub (solid under bark) at average extraction distances on 360-412 m for loads of sawlogs and 0.43-0.66 l/m3sub (458-514 m) for loads of pulpwood. 61-62% of that fuel was consumed during loading and driving during loading. The forwarders consumed 0.23-0.38 l/100 m driving and the difference was only 10% with and without load. In the questionnaire survey, the fuel consumption averaged 0.62 l/m3sub (sawlogs and pulpwood, 318 m average extraction distance) for final felling (16-20 tonne forwarders) and 0.92 l/m3sub (644 m) for thinning (11-14 tonnes). An exception was 2.5 tonne forwarders that consumed only 0.35-0.37 l/m3sub (120-180 m). 89% of the extracted volume in the accounting data was from thinnings and the fuel consumption was in average 0.67 l/m3sub (100-200 m) for 9 to11 tonne forwarders. More difficult terrain conditions, the use of tracks and wheel-chains and one more assortment in the questionnaire survey are the most probable reasons for higher fuel consumption than in the field study. At long extraction distances it is especially important to utilize the maximum load capacity to benefit low fuel consumption on m3 basis

Technical Design Report for the LUXE experiment

This Technical Design Report presents a detailed description of all aspects of the LUXE (Laser Und XFEL Experiment), an experiment that will combine the high-quality and high-energy electron beam of the European XFEL with a high-intensity laser, to explore the uncharted terrain of strong-field quantum electrodynamics characterised by both high energy and high intensity, reaching the Schwinger field and beyond. The further implications for the search of physics beyond the Standard Model are also discussed

Technical Design Report for the LUXE experiment

This Technical Design Report presents a detailed description of all aspects of the LUXE (Laser Und XFEL Experiment), an experiment that will combine the high-quality and high-energy electron beam of the European XFEL with a high-intensity laser, to explore the uncharted terrain of strong-field quantum electrodynamics characterised by both high energy and high intensity, reaching the Schwinger field and beyond. The further implications for the search of physics beyond the Standard Model are also discussed

Granular Jamming as Controllable Stiffness Mechanism for Medical Devices

peer reviewedEndoscopic medical devices require high bending flexibility to navigate through tortuous channels while exhibiting some stiffness to exert force on tissues. The granular jamming is a solution which can be implemented at the tip or along the body of these devices to control their stiffness. In this work, the stiffness of sphere packings is studied experimentally and modeled by Discrete Element Method (DEM). The secant stiffness, at a medium level of strain, is evaluated by means of special vacuum assisted triaxial compression tests using polydisperse glass beads as granular material. A cycling method is performed during the experimental procedure to ensure the repeatability of the measurements by eliminating the initial experimental conditions and to be compared to the DEM results. The model has been calibrated by fitting the experimental curves and varying the contact stiffness of the particles, the contact friction angle, the grain size distribution and the confining stress. This numerical tool is used for forecasting the behavior outside the experimental conditions. Among all parameters, the pressure difference shows the largest effect on the stiffness change and can therefore be used as the stimulus for future controllable stiffness medical devices

The concentration of carbon monoxide in the breathing areas of workers during logging operations at the motor-manual level

Objectives: This article compares 2 variants of logging technologies at the motor-manual level: variant A – cutting and delimbing by means of a petrol chainsaw, skidding with the use of a cable winch mounted on a tractor (67–74 kW); variant B – cutting by means of a petrol chainsaw, skidding, debranching and cutting to length by means of a processor aggregated with a farm tractor (61 kW). Material and Methods: Direct dosimetry and non-parametric (moving block bootstrap) methods were used in order to specify the characteristics of the collected sets. Results: Bootstrap average values show that the average CO concentration at a skidding tractor operator’s station during early thinning was 2.54 mg×m–3. At processor operator’s station it amounted to 10.35 mg×m–3. Such results allow to conclude that a higher CO concentration at the above-mentioned 2 work stations was observed during early thinning. In the case of a petrol chainsaw operator, it was observed that the permissible exposure limit (23 mg×m–3) was exceeded and the short-term permissible exposure limit (117 mg×m–3) was not. The average concentration value for a chainsaw operator working individually during late thinning interventions was substantially lower (15.01 mg×m–3), which results from the lack of technological pressure that can be observed while cooperating with a processor operator. Conclusions: The risk increases along with conditions that generate the concentration of exhaust produced by 2-stroke petrol chainsaw engines

Technical Design Report for the LUXE experiment

This Technical Design Report presents a detailed description of all aspects of the LUXE (Laser Und XFEL Experiment), an experiment that will combine the high-quality and high-energy electron beam of the European XFEL with a high-intensity laser, to explore the uncharted terrain of strong-field quantum electrodynamics characterised by both high energy and high intensity, reaching the Schwinger field and beyond. The further implications for the search of physics beyond the Standard Model are also discussed