Effects of Sieve Size on Chipper Productivity, Fuel Consumption and Chip Size Distribution for Open Drum Chippers

Chip size distribution is an important quality variable not only for buyers of forest fuels, but also for chipping contractors as it influences both fuel consumption and productivity of chippers. Studies of disc chippers and of drum chippers with closed drums have shown that increased chip target length increases chipper productivity and decreases fuel consumption per ton of chips produced. For open drum chippers, chip length is partly controlled by the mesh size in the sieve. In order to evaluate how this sieve affects productivity and fuel consumption of chippers, two open drum machines for professional chipping of forest fuels were studied. Small chippers were represented by a Kesla 645, and larger ones by an Eschlböck Biber 92. The Kesla 645 was studied with 25, 50, and 100 mm sieves and the Biber 92 with 35, 50, and 100 mm sieves. With the 100 mm sieve the Kesla chipper produced 14.5 oven dry ton (odt) of chips per effective hour and the Biber 30.0 odt per effective hour. Fuel consumption per odt was 3.0 l for the Kesla and 2.1 l for the Biber. A reduction of sieve mesh size decreased productivity and increased fuel consumption for both machines. Reducing the mesh size decreased the size of produced chips for the Kesla, but not for the Biber. The sieve on the Biber seems to be a safety measure against oversized pieces whereas chip size is, as on a closed drum chipper, mainly controlled by the cut length of the knives

Laser capture microdissection of gonads from juvenile zebrafish

<p>Abstract</p> <p>Background</p> <p>Investigating gonadal gene expression is important in attempting to elucidate the molecular mechanism of sex determination and differentiation in the model species zebrafish. However, the small size of juvenile zebrafish and correspondingly their gonads complicates this type of investigation. Furthermore, the lack of a genetic sex marker in juvenile zebrafish prevents pooling gonads from several individuals. The aim of this study was to establish a method to isolate the gonads from individual juvenile zebrafish allowing future investigations of gonadal gene expression during sex determination and differentiation.</p> <p>Methods</p> <p>The laser capture microdissection technique enables isolation of specific cells and tissues and thereby removes the noise of gene expression from other cells or tissues in the gene expression profile. A protocol developed for laser microdissection of human gonocytes was adjusted and optimised to isolate juvenile zebrafish gonads.</p> <p>Results</p> <p>The juvenile zebrafish gonad is not morphologically distinguishable when using dehydrated cryosections on membrane slides and a specific staining method is necessary to identify the gonads. The protocol setup in this study allows staining, identification, isolation and subsequent RNA purification and amplification of gonads from individual juvenile zebrafish thereby enabling gonadal gene expression profiling.</p> <p>Conclusion</p> <p>The study presents a protocol for isolation of individual juvenile zebrafish gonads, which will enable future investigations of gonadal gene expression during the critical period of sex differentiation. Furthermore, the presented staining method is applicable to other species as it is directed towards alkaline phosphatase that is expressed in gonocytes and embryonic stem cells, which is conserved among vertebrate species.</p

A common Nordic-Baltic costing framework for road, rail and sea transport of roundwood

Transport cost calculations are fundamental for most types of transport research. Applications can range from estimating the cost benefits of developing transport technologies (e.g. increased truck GVWs) to comparing profitability between alternative infrastructure investments (e.g. rail or sea terminals). Most stakeholders rely on a favourite spreadsheet, however these vary considerably with respect to functionality, resolution and transparency. During 2019 and 2020 the NB Nord Road and Transport group has worked towards a common Nordic-Baltic costing framework for road, rail and sea transport. The goal has been to propose a general model per transport method which is user-friendly, while retaining the necessary resolution and functionality to model actual costs for specific transport orders or contracts. The handbook provides: a) complete explanation of its formulas, b) calculation examples and c) a corresponding Excel spreadsheet...publishedVersio

Effects of Sieve Size on Chipper Productivity, Fuel Consumption and Chip Size Distribution for Open Drum Chippers

Chip size distribution is an important quality variable not only for buyers of forest fuels, but also for chipping contractors as it influences both fuel consumption and productivity of chippers. Studies of disc chippers and of drum chippers with closed drums have shown that increased chip target length increases chipper productivity and decreases fuel consumption per ton of chips produced. For open drum chippers, chip length is partly controlled by the mesh size in the sieve. In order to evaluate how this sieve affects productivity and fuel consumption of chippers, two open drum machines for professional chipping of forest fuels were studied. Small chippers were represented by a Kesla 645, and larger ones by an Eschlböck Biber 92. The Kesla 645 was studied with 25, 50, and 100 mm sieves and the Biber 92 with 35, 50, and 100 mm sieves. With the 100 mm sieve the Kesla chipper produced 14.5 oven dry ton (odt) of chips per effective hour and the Biber 30.0 odt per effective hour. Fuel consumption per odt was 3.0 l for the Kesla and 2.1 l for the Biber. A reduction of sieve mesh size decreased productivity and increased fuel consumption for both machines. Reducing the mesh size decreased the size of produced chips for the Kesla, but not for the Biber. The sieve on the Biber seems to be a safety measure against oversized pieces whereas chip size is, as on a closed drum chipper, mainly controlled by the cut length of the knives

Costing models for road, rail and sea transport of roundwood

Costing models for roundwood transports have been developed by NB Nord co-operation with Road and Transport group, coordinated by Pirjo Venäläinen of Metsäteho, and consisting of transport researchers from all member institutes including: Dag Fjeld, NIBIO, Kari Väätäinen, Luke, Henrik von Hofsten and Daniel Noreland, Skogforsk, Ingeborg Callesen, IGN KU and Andis Lazdins, Silava. In general, the NB Nord costing models follow classical cost assessments for material transportations with specialities of each transport mode. Models are aimed at calculating the operating costs of roundwood transports either on a yearly basis as for road and rail transports or on a voyage basis as for sea transports. In addition, models can be used for calculating performance indicators of transports such as annual working hours, loads, transported tons of timber, transport distances etc. As an output, key performance indicators for costing include costs per metric ton, per km, per tkm, per load, per hour and per year. The models enable sensitivity analysis and direct comparison of transport costs between e.g. alternative supply chains, transport modes and countries of interest. “A common Nordic-Baltic costing framework for road, rail and sea transport of roundwood” -handbook guides using the costing models and it is available at https://hdl.handle.net/11250/2723839</a

Overview of Global Long-Distance Road Transportation of Industrial Roundwood

The aim of the study was to provide a comprehensive overview of global long-distance road transportation of industrial roundwood. The study focused on the maximum gross vehicle weight (GVW) limits allowed with different timber truck configurations, typical payloads in timber trucking, the road transportation share of the total industrial roundwood long-distance transportation volume, and the average long-distance transportation distances and costs of industrial roundwood. The study was carried out as a questionnaire survey. The questionnaire was sent to timber transportation logistics experts and research scientists in the 30 countries with the largest industrial roundwood removals in Europe, as well as selected major forestry countries in the world (Argentina, Australia, Brazil, Canada, Chile, China, Japan, New Zealand, South Africa, Türkiye, the United States of America and Uruguay) in February 2022, and closed in May 2022. A total of 31 countries took part in the survey. The survey illustrated that timber trucking was the main long-distance transportation method of industrial roundwood in almost every country surveyed. Road transportation averaged 89% of the total industrial roundwood long-distance transportation volume. Timber truck configurations of 4 to 9 axles with GVW limits of around 30 tonnes to over 70 tonnes were most commonly used. The results indicated that higher GVW limits allowed significantly higher payloads in timber trucking, with the lowest payloads at less than 25 tonnes, and the highest payloads more than 45 tonnes. The average road transportation distance with industrial roundwood was 128 km, and the average long-distance transportation cost in timber trucking was €11.1 per tonne of timber transported. In the entire survey material, there was a direct relationship between transportation distance and transportation costs and an inverse relationship between maximum GVW limits and transportation costs. Consequently, in order to reduce transportation costs, it is essential to maximise payloads (within legal limits) and minimise haul distances. Several measures to increase cost- and energy-efficiency, and to reduce greenhouse gas emissions in road transportation logistics, are discussed in the paper. On the basis of the survey, it is recommended that up-to-date statistical data and novel research studies on the long-distance transportation of industrial roundwood be conducted in some countries in the future