Badanie możliwości zastosowania łodyg malin do produkcji brykietów

The paper presents research on the strength properties of raspberry stems from cuttings and their suitability for the production of briquettes. For this purpose, the cutting resistance, Charpy impact and bending stiffness of raspberry stalks were determined. Then briquettes were made to define their mechanical strength for different moisture contents. After that the heat of combustion of the briquettes was checked.Praca przedstawia badania dotyczące właściowości wytrzymałościowych łodyg malin pochodzących z przycinki krzewów oraz ich przydatności do produkcji brykietów. W tym celu określno opory cięcia, udarność i sztywność na zginanie łodyg malin. Następnie wykonano z nich brykiety, określono ich wytrzymałośc mechaniczną dla różnych zawartości wilgoci oraz sprawdzono ciepło spalania

An Attempt to Model the Surface Pressures of Apples Using the Finite Element Method

Apples are the most popular fruits grown in Polish orchards. In order to obtain the best quality fruit, it is necessary to improve plantation maintenance, fruit harvesting, and processing. Given that many fruits are exposed to external factors, including forces that adversely affect their structure—causing them to crack, bruise, or crush—it is necessary to provide conditions that do not adversely affect their quality. Therefore, the aim of this article was to develop a simplified model of an apple that could be tested under different loads using the finite element method. The parameters of the model were selected to reflect the actual apple as accurately as possible. To assess the apples under impact load, as well as the construction of the FEM model, concrete and wooden substrates were used, where apples were dropped from height of 10 mm and 30 mm. Due to this research, an apple model was obtained that reflects the actual object very well (high R2 coefficient). In addition, the layering and distribution of surface pressures of the real and model objects from the distribution are presented. This shows that the constructed model corresponds to the behaviour of the biological material, subjected to loads in real conditions

Modelowanie korzenia marchwi przy użyciu metody elastooptycznej

This paper presents elastooptical method for assessment of carrot root displacement under impact load. The main purpose of this study involved an analysis of cross-section model of carrot root performance. The investigation by means of the polariscope was conducted. In each phase under load, a characteristic isochromatic pattern distribution was determined. Tested model was made of the polyurethane elastomer which provided mechanical properties similar to biological features. Stress distribution in selected cross-sections as well as in two mutually perpendicular σx and σy directions was also determined. On basis of the results a cross-section model of carrot root has been performed.W pracy przedstawiono elastooptyczną metodę oceny przemieszczenia korzeni marchwi pod obciążeniem udarowym. Głównym celem badania była analiza przekrojowego modelu wydajności korzenia marchwi. Przeprowadzono badanie za pomocą polariyskopu. W każdej fazie pod obciążeniem określono charakterystyczny rozkład wzoru izochromatycznego. Testowany model został wykonany z elastomeru poliuretanowego, który zapewniał właściwości mechaniczne podobne do właściwości biologicznych. Określono również rozkład naprężeń w wybranych przekrojach oraz w dwóch wzajemnie prostopadłych kierunkach σx i σy. Na podstawie wyników wykonano model przekroju korzenia marchwi

Determination of Permissible Load in Selected Parts of the Human Musculoskeletal System While Feeding Cows with Maize Silage

Farmers belong to the group of high risk in terms of developing work-related musculoskeletal disorders. A series of tasks, which are often performed in an uncomfortable position, loads exceeding farmers’ physical abilities, as well as high repetition of work movements, all contribute significantly to the development of irreversible changes in the musculoskeletal system. Taking into account the above-mentioned circumstances, this study aimed at workload assessment expressed in maximal voluntary contraction (%MVC) while delivering dairy-cattle feed. In the initial phase of this study, a questionnaire was carried out, based on which a load of individual segments of the musculoskeletal system during work was subjectively assessed. On this basis, the areas of the musculoskeletal system were selected in which a risk of the ailments’ occurrence was the highest. These studies were carried out directly on farms, where the surface electromyography (sEMG) method was used. On the basis of obtained results, the permissible human load was determined based on mass of the shovel which was used to load and unload maize silage. The obtained results can be used to ensure safe conditions while performing work with high muscle exertion

Simple Method for Apples’ Bruise Area Prediction

From the producers’ point of view, there is no universal and quick method to predict bruise area when dropping an apple from a certain height onto a certain type of substrate. In this study the authors presented a very simple method to estimate bruise volume based on drop height and substrate material. Three varieties of apples were selected for the study: Idared, Golden Delicious, and Jonagold. Their weight, turgor, moisture, and sugar content were measured to determine morphological differences. In the next step, fruit bruise volumes were determined after a free fall test from a height of 10 to 150 mm in 10 mm increments. Based on the results of the research, linear regression models were performed to predict bruise volume on the basis of the drop height and type of substrate on which the fruit was dropped. Wood and concrete represented the stiffest substrates and it was expected that wood would respond more subtly during the free fall test. Meanwhile, wood appeared to react almost identically to concrete. Corrugated cardboard minimized bruising at the lowest discharge heights, but as the drop height increased, the cardboard degraded and the apple bruising level reached the results as for wood and concrete. Contrary to cardboard, the foam protected apples from bruising up to a drop height of 50 mm and absorbed kinetic energy up to the highest drop heights. Idared proved to be the most resistant to damage, while Golden Delicious was medium and Jonagold was least resistant to damage. Numerical models are a practical tool to quickly estimate bruise volume with an accuracy of about 75% for collective models (including all cultivars dropped on each of the given substrate) and 93% for separate models (including single cultivar dropped on each of the given substrate)