1,720,967 research outputs found
Biomasse legnose
No full textPer comprendere le strategie di azione e i modelli di filiera inerenti il settore delle biomasse legnose di origine agricolo e forestale, si sono prese in considerazione le misure che attualmente si stanno applicando a livello europeo e nazionale
Planning forest biomass supply chain for energetic use through site analysis
No full textA spatial analysis methodology should be required to define forest biomass availability for energetic use and, in the same time, to support decisions on the most appropriate supply logistic.
The methodology has to consider terrain, road network and forest stand characteristics, as these main site features change in space and in time. In fact, consequently these factors influence supply cost that are straight connected to biomass localisation, quality of road network and machine accessibility.
In order to evaluate the feasibility of supplying forest biomass (logging residue or un-merchantable logs) and consequently to estimate their amount and supply cost, a site analysis was carried out by a GIS methodology.
Since a GIS methodology was previously developed for supporting raster analysis, in this case study a network study based on vector analysis were consequently developed in order increase the transport supply distance data quality.
With the aim to define a forest biomass for energetic use supply basin a first rough Decision Support System was drafted considering road network and the amount of looking residues or un-merchantable logs left at forest roadside
Wood biomass boilers and heating plants in north-eastern italy: which strategy to boost a sustainable local supply chain?
No full textUse of wood biofuel for heating application is increasing in Italy. In some North-eastern areas, woody biomass partially contributes to cover the thermal energy demand. The actual use of wood fuel is strictly connected to founds promoted by regional governments. Aim of this study is to evaluate the demand and the offer of wood fuel energy, at regional and basin level, by analysing the distribution of boilers, forest and sawmill wood fuel resources.
Wood fuel procurement is also investigated by interviews. Boilers are mainly located close to the sources of fuel (forest and sawmills). Two basins on 44 considered in the study have bigger demand than offer and are supplying fuel from other basins that exceed in resources. Wood fuel supply must be improved adopting storages to dry fuel before combustion
Logging operations in high value hardwood mixed plantations
No full textIn Italy some agricultural areas have been planted with high value hardwood mixed plantations (mainly walnut or cherry trees) realized with a technique that provides benefits also for the presence of accessory species. The purpose of this work is to study intermediate cutting operations in mixed plantations. Two different plantations of walnut (with poplar and other fitting trees), situated in Lombardia region (Northern Italy), were investigated. In Casal Buttano plantation walnut has a planting distance of 10x14 m and it is combined with poplar (5x14 m distance). Between the two species there are two shrub rows (cob hazel and elder) and a common European alder row. In walnut rows, the main species is alternated with Eleagnus umbellata shrubs. In San Matteo delle Chiaviche plantation the planting distance between trees is 3x3.5 m. Trees species are walnut, poplar, common European alder and a shrub (Eleagnus umbellata). During intermediate cutting operation poplar needs to be felled providing no damages to standing walnuts. Because of the different distance between species in the two stands, different logging methods were needed. Time studies were carried out to analyse two different logging methods. In Casal Buttano plantation cob hazel shrubs were cut with a cutting-chipper machine that provided biomass for heating. During poplar logging an operator with chainsaw felled the trees assisted by an excavator equipped with a loading grapple; the trees were then forwarded on a tractor bunk. In San Matteo delle Chiaviche plantation a chainsaw operator felled poplar in the right direction supported by an operator with felling lever; the trees were skidded by tractors. Productivity and costs of the two methods were calculated. Both adopted logging methods did not cause any damage to the standing walnuts. First method might be suitable when rows of poplar and walnuts are separated by an accessory species row, in order to avoid damages caused by the excavator. Second method is advisable in stands where rows of poplar and walnuts are adjacent, without any accessory species in the middle
Wood chipping service: an analysis approach in Northeastern Italy
Get PDFWith the spread of wood chip boilers and district heating, the chipping service in North-eastern
Italy is gradually growing.
With a GIS based approach is possible to define operative areas of chipping services in relation to the
availability of wood biomass that potentially can be chipped. By evaluating the amount of wood that
could be chipped, it is possible to check if chippers have the warranty of operating time so that the
machine initial investment is justified. Moreover, the possibility to buy and use further chippers, that can
work in a sustainable way with the potentially available biomass, can be evaluated.
Wood biomass for chipping service, potentially available from forest and sawmill, is estimated and
combined to chipping service headquarters distribution and to road network. Chipping service
productivities and costs are considered for two classes of machines: big and medium power class. In the
supposed conditions, the study highlights that the current distribution of chippers in the North-eastern
Italy require about 70 000 t/y of woody biomass from forest and wood industry. Some more biomass is
still available to be chipped, but actually it can be covered with a more far working distance. Moreover
not all estimated wood biomass can be technically supplied because of high cost
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Comparison of biomass feedstock supply and demand in Northeast Italy
Get PDFThis study uses Geographical Information Systems (GIS) to estimate woody biomass supply
and demand in Northeast Italy. Demand is estimated using census data on boilers and
supply calculations are derived from data on timber harvests and mill operations. The
analysis is done with GIS using Large Scale Analysis at a broader resolution (for the entire
region) and Small Scale Analysis at a finer resolution (for the Primiero valley only), with
added information on tree species, road networks and logging systems. From large scale
analysis demand results to be about 163 000 MWh, corresponding to about 71 000 tonnes
per year of fuel, with a moisture content of 50 percent. As shown by results from a small
scale analysis, the Primiero valley has a deficit of 21 400 MWh. A more thorough analysis
shows that 93 percent of logging operations can be performed with cable cranes and that
high quality chips derived from forest biomass amount to only 335 MWh of energy (20
percent of the total). The deficit calculated at a small scale confirms the value obtained in
the large scale calculation.
Analysis of the demand-supply balance will be helpful for decision makers and politicians
and should be taken into account when allocating subsidies for new boilers or district
heatin
- …
