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This article provides an overview of the characterization and construction of a low-cost compact hammer mill for laboratory use to homogenize natural fibers of Elaeis guineensis and Acrocomia sp., in order to reduce the particle size of these fibers and other materials to study their physicochemical properties. The hammer mill was characterized by determining the theoretical output angular velocity in the rotor, the energy required per unit of mass during grinding (kJ/kg), the rotational speed of the rotor with its respective uncertainty extended to 95 %, the calculation of the stress and the safety factor in the rotor and hammers, the resulting particle size of the empty bunch of fruit oil palm (Elaeis guineensis) and the nutshell of the macaw fruit palm (Acrocomia sp.). The hammer mill was built with materials that can be obtained in an industrial hardware store, and a recycled vehicle part. The construction methodology was based on precision machining and metalworking. Residual lignocellulosic materials, such as the empty fruit oil palm cluster, the nutshell of the macaw fruit palm, rocks, coconut shell, wood, sludge, and aluminum slag were ground using this device. The construction of the hammer mill is compact and versatile, and it allows grinding a wide variety of materials for research processes that require the reduction of organic and inorganic materials. Due to its modest size, it can be placed in a laboratory, and since its powered by 110 V, no special requirements are necessary. [ABSTRACT FROM AUTHOR]

The article presents a proposal for the design of an Ecological Complex for the management of pineapple agricultural waste in Costa Rica. Pineapple cultivation generates waste called "rastrojo" that affects nearby communities. The author proposes an integrated management system that includes the extraction of plant fibers, composting, and the use of the remaining material for mushroom cultivation. The architectural design of the complex seeks to guarantee a local impact and uses laminated wood structures and suitable enclosures for the conditions of the humid tropical forest. However, it is emphasized that this project is specific to the locality of Katira and is not applicable to other areas without considering specific conditions. [Extracted from the article]

Nowadays it is essential to minimize costs and environmental impact to rehabilitate and construct roads. In the last years there have been numerous studies on the reuse of recycled aggregates in structural layers of road and concrete manufacture. Other types of residues may be applied for these purposes, but currently are taken to landfill or used in applications with poor added value. In particular, due to the growing demand on clean energy, in Andalusia has been developed an important sector around of electric energy generation from biomass combustion. This system of renewable energy generation produces an increase of by-products of combustion, called biomass ashes (BA) that may be biomass bottom ashes (BBA) or biomass fly ashes (BFA). The aim of this work is to study the reuse of BBA in linear works construction, thus increasing its value as a by-product, and avoids the transfer to landfill. Namely, the research are made on the application of these ashes in esplanades as stabilizer material of expansive soils. [ABSTRACT FROM AUTHOR]

In order to evaluate and select cultivars of soybean (Glycine max (L) Merr) for forage purposes, an experiment was conducted using a randomized complete block design with 6 replications. The experimental materials used were 9 cultivars from the germplasm bank DANAC Foundation and cultivar CIGRAS-06 from the Research Center of Grain and Seeds of the University of Costa Rica. The variables studied were those related to plant architecture, total biomass production in the reproductive R6, grain yield and some bromatological variables. Statistical analyzes showed significant differences for the variables under study. The cultivars with the highest biomass yields were CIGRAS-06, FP93-1935, FP93-1924 and FP90-6102, with 17245, 13075, 13066 and 12587 kg.ha-1 of dry matter (DM). The higher content of crude protein (CP) in the pods were FP90-10205, FP93-1930 and FP92-1904, with 24.2, 23.7 and 21.0%, respectively. And at leaf-level, cultivars FP93-1935, FP92-4906 and FP90-7102 with 25.5, 24.9 and 23.0%, respectively. For grain production, cultivars showing high potential were CIGRAS-06, FP93-1924, FP90-6102 and FP90-16103, exceeding 3500 kg.ha-1. [ABSTRACT FROM AUTHOR]

With the objective of promoting sunflower as a forage crop, planting densities of 75.000, 100.000, 125.000 y 150.000 plants.ha-1 were evaluated on biomass yield for cattle feeding. Data was taken at the beginning of blooming time. A complete randomized blocks design was used. The ANOVA showed that planting density significantly (p≤0.05) modified the sunflower biomass yield. At 75.000 plants.ha-1, plants showed the highest values per plant in stem diameter (1.18 cm), leaf dry weight (30.3 g), stem dry weight (50.7 g), and plant total dry weight (98.4 g); in addition, the leaf:stem ratio was always smaller than 0.70. On the other hand, with 150.000 plants.ha-1, the highest values per hectare were obtained in plant height (102.3 cm), leaf dry weight (3.3 t.ha-1), stem dry weight (4.8 t.ha-1), and plant total dry weight (9.5 t.ha-1). Thus, the highest planting density, affected negatively the biomass per plant, while the biomass per hectare was positively affected. [ABSTRACT FROM AUTHOR]