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Handling and transportation properties of rapeseed biomass as affected by particle size

Bojanowska Milena

Zeszyty Naukowe Akademii Morskiej w Szczecinie

2023

nr 74 (146)

5--15

Rapeseed by-products of seeds de-oiling, particularly expellers and post-extracted meal, are currently considered an important biomass that can be used as an alternative energy source, either in raw form or after conversion to biochar. Rapeseed biomass represents a difficult-to-handle cargo, mainly due to its sensitivity to mechanical, climatic, and biological impacts, as well as its dusty nature. This study aims to determine the physical properties of rapeseed meals and their fractions. Morphological and chemical features of six particle sets are investigated in order to explain the variation in their physical properties having importance in handling and transportation processes. The true density of fractions increases when the particle size decreases due to the diminishing quantitative share of seed coats. No correlation is observed between true and bulk densities, as the particle shape, surface sculpture, and adhesion affect the mutual particle arrangements. Along with a decrease in the particle size from 0.4 mm, a rapid decrease in the flowability is observed. The tendency of the finest dust (d < 0.075 mm) to form agglomerated complexes causes its lower bulk density, higher porosity, and higher angles of repose in comparison to coarse dust (0.075–0.4 mm). It is concluded that a relatively low tendency to free flowing of natural RSM is mainly caused by its wide-ranging particle size distribution and their geometry differentiation, which facilitate mutual particle interlockings. The known cases of blockages of silos, bins, hoppers, and transfer chutes may be mainly caused by the powder fractions (< 0.2 mm), with a much lower flowability than other particles.

Determinants of prices increase of agricultural commodities in a global context

Borychowski M., Czyżewski A.

Management

2015

Vol. 19, no. 2

152--167

The main objective of this article is to present the determinants of increase in agricultural commodity prices after 2006. The other specific aim is to show the factors affecting agricultural raw materials and food prices in the global context. This article is a review paper of the determinants of recent commodity and food prices spikes. However, it provides an outlook on these determinants that were the most important for the increases in the last decade. The last part of the article (conclusions) to some extent is a synthesis of considerations and includes the authors’ opinions concerning determinants and an attempt to identify which ones were the most important in the growth of agricultural commodity prices. These increases in agricultural commodity prices resulted from many factors and it is very difficult to separate the individual impact of each of them, because they occurred in parallel. However, it is possible to indicate several main reasons for these price increases, which are: adverse changes in supply-demand relations in agricultural markets, increases in oil prices (and increases of the volatility of those prices), development of biofuel production from agricultural commodities (the first generation biofuels), dollar depreciation, an increase in operations of a speculative nature on commodity markets and improper economic policy that created an environment for the growth of prices of agricultural products.

Celem głównym artykułu jest ukazanie determinant wzrostu cen surowców rolnych, które szczególnie zaznaczyły się w ich wzrostach po 2006 roku. Jego realizację wspiera cel podrzędny, którym jest przedstawienie makroekonomicznych czynników cenotwórczych na rynkach rolnych. Artykuł ma charakter przeglądowy, z którego wynikają jednak pewna ocena oraz pogląd na te determinanty, które dla wzrostów cen produktów rolnych były najistotniejsze. Podsumowanie stanowi syntezę rozważań i zawarto w nim opinie autorów dotyczące poszczególnych determinant wraz z próbą wskazania, które z nich miały największe znaczenie we wzrostach cen surowców rolnych. Wzrosty cen surowców rolnych w ostatnich latach wynikały z działania wielu czynników i w gruncie rzeczy trudno jest wyizolować osobny wpływ każdego z nich, ponieważ czynniki te występowały równolegle. Można natomiast wskazać główne determinanty tych wzrostów cen, są nimi: niekorzystne zmiany relacji podażowo-popytowych na rynkach rolnych, wzrosty cen ropy naftowej (i wzrosty zmienności tych cen), rozwój produkcji biopaliw z surowców rolnych, deprecjacja dolara, wzrost działań o charakterze spekulacyjnym na rynkach towarowych oraz niewłaściwa polityka gospodarcza, która stworzyła środowisko dla wzrostu cen produktów rolnych.