Search Results (5)

A common method of silage production in Europe is based on the use of cylindrical bales wrapped with polyethylene films. In this study, several modifications of composition of these films were tested for their impact on the microorganisms involved in the ensiling process. Different additives, including nanosilver particles and microcellulose, were analyzed upon the first stage of the experiment. In the second stage, the usability of recycled polyethylene as a film component was assessed. The forage value after ensiling was determined during storage, based on analyses of the content of crude fiber, nitrate nitrogen, total protein, sugars, acids (lactic, acetic, butyric and propionic), pH and dry matter. Microbial forage quality was evaluated by analyses of growth of lactic acid bacteria (LAB) compared to the number of undesirable aerobic bacteria, yeasts and molds. Film properties were also characterized. No statistically significant (p < 0.05) differences were shown for the tested film formulae as compared to standard commercial films. In the second experimental stage, an elevated pH and a slightly higher content of acids were observed for the tested films than for the control sample. In addition, for standard PE film supplemented with nanosilver, a higher number of LAB was detected on the inner surface of the film and in the ensiled material. Full article

For the assumed bale volume, its dimensions (diameter, height), minimizing the consumption of the plastic film used for bale wrapping with the combined 3D method, depend on film and wrapping parameters. Incorrect selection of these parameters may result in an optimal bale diameter, which differs significantly from its height, while in agricultural practice bales with diameters equal or almost equal to the height dominate. The aim of the study is to formulate and solve the problem of selecting such dimensions of the bale with a given volume that the film consumption is minimal and, simultaneously, the bale diameter is equal or almost equal to its height. Necessary and sufficient conditions for such equilibria of the optimal bale dimensions are derived in the form of algebraic equations and inequalities. Four problems of the optimal bale dimension design guaranteeing assumed equilibrium of diameter and height are formulated and solved; both free and fixed bale volume are considered. Solutions of these problems are reduced to solving the sets of simple algebraic equations and inequalities with respect to two variables: integer number of film layers and continuous overlap ratio in bottom layers. Algorithms were formulated and examples regarding large bales demonstrate that they can handle the optimal dimensions’ equilibria problems. Full article

The production of silage is carried out in cylindrical bales covered with polyethylene foils. In this study, a novel approach was tested towards obtaining an innovative composition of these films. In the first stage of the experiment, different additives, including microcellulose and nanosilver particles, were analyzed. The second stage was aimed at testing the applicability of recycled polyethylene as a film component. The forage value after ensiling was assessed during storage. In order to evaluate the microbial forage quality, the abundance of lactic acid bacteria was determined and compared with the number of aerobic bacteria, yeasts, and molds. The foil properties were also analyzed with the appropriate chemical and microbiological methods. The results showed no significant differences (p < 0.05) between the standard commercial films and tested formulae. In the second stage, obtained results suggested that the film with the addition of nanosilver may be successfully used in agriculture. Full article

A conventional method for wrapping round bales of agricultural materials by wrappers with a rotating table or with rotating arms is considered. In contemporary agriculture, the demand for minimal consumption of the film used to wrap bales is very high, in order to apply this method with lower cost and less damage to the environment. A combined model-based problem of such a design, focusing on the width of stretch film and the overlap between adjacent film strips that minimizes film consumption, was mathematically formulated and solved. It was proven that the complete set of optimal film widths is defined by a simple algebraic equation described in terms of film, bale, and wrapping parameters. The optimal overlap ratios were found to be irreducible fractions in which the dividend is the divisor minus one; however, only the first three factions, $\frac{1}{2},\frac{2}{3},\mathrm{and}\frac{3}{4}$ , are practically significant. Next, the robustness to disturbances in the functioning of an actual bale wrapper, which leads to overlap ratio uncertainty, is examined. It was shown that, unfortunately, the optimal film widths applied together with the optimal overlaps do not provide any robustness to overlap variations. To overcome this inconvenience, the problems of a choice of the best commercially available film width guaranteeing minimal film consumption or maximal tolerance on the overlap uncertainty were formulated and solved. A new algorithm for a robust design of wrapping parameters was developed, motivated, and numerically verified to achieve a trade-off between satisfactory robustness and low film usage. For the resulting wrapping parameters, near-optimal film usage was achieved; the relative errors of the minimal film consumption approximation did not exceed 4%. It was proven that for the overlap, slightly more than 50%, i.e., 51% or 52%, provides both optimality and robustness of the overlap over disturbances, which are ensured regardless of the number of film layers. Moreover, it was found that for these overlaps and for the commercially available film widths selected according to the algorithm, the film consumption was more than twice as small than the film usage for exactly 50% overlap, if the actual overlap was smaller than pre-assumed. Similarly, an overlap of slightly more than the commonly used 67% will result in about 30% to 40% reduction in film usage in the presence of unfavorable disturbances, depending on the number of film layers and wrapping parameters. Full article

Year-round operation of biorefineries can be possible only if the continuous flow of cellulosic biomass is guaranteed. If corn (Zea mays) stover is the primary cellulosic biomass, it is essential to recognize that this feedstock has a short annual harvest window (≤1–2 months) and therefore cost effective storage techniques that preserve feedstock quality must be identified. This study evaluated two outdoor and one indoor storage strategies for corn stover bales in Iowa. High- and low-moisture stover bales were prepared in the fall of 2009, and stored either outdoors with two different types of cover (tarp and breathable film) or within a building for 3 or 9 months. Dry matter loss (DML), changes in moisture and biomass compositions (fiber and ultimate analyses) were determined. DML for bales stored outdoor with tarp and breathable film covers were in the ranges of 5–11 and 14–17%, respectively. More than half of the total DML occurred early during the storage. There were measurable differences in carbon, hydrogen, nitrogen, sulfur, oxygen, cellulose, hemi-cellulose and acid detergent lignin for the different storage treatments, but the changes were small and within a narrow range. For the bale storage treatments investigated, cellulose content increased by as much as 4%s from an initial level of ~41%, hemicellulose content changed by −2 to 1% from ~34%, and acid detergent lignin contents increased by as much as 3% from an initial value of ~5%. Tarp covered bales stored the best in this study, but other methods, such as tube-wrapping, and economics need further investigation. Full article