Single crystals of the metastable phase of KCOPO₄ (α-KCP) have been synthesized in a gel of tetra-methoxysilane. The crystals have a hexagonal symmetry which belongs to space group P6₃ (cell parameters a = 18.206(1), c = 8.5135(8) [Å] and Z = 24). The crystals have been characterized by x-ray diffraction and by polarized light microscopy. The magnetoelectric properties of this compound have been studied at 4.4 K. No linear magnetoelectric effect has been detected and all coefficients of the tensor corresponding to the quadratic magnetoelectric effect (ME)_H, have been determined at 4.4 K: β₁₂₃ = -β₂₁₃ = 2.3 10⁻¹⁸, β₁₁₃ = β₂₂₃ = 7.1 10⁻¹⁸, β₃₁₁ = β₃₂₂ = 12.2 10⁻¹⁸ and β₃₃₃ = 7.2 10⁻¹⁸ in [s A⁻¹] (estimated error less than 5%). The absence of a linear magnetoelectric effect and the form of the tensor of the quadratic effect indicate that the magnetic symmetry of the crystal at this temperature must belong either to the antiferromagnetic magnetic point group 6′ or to the paramagnetic one 61′. The pyroelectric effect was also measured confirming polar character of the structure.

An important element of a solar installation is the storage tank. When properly selected and operated, it can bring numerous benefits. The presented research relates to a project that is implemented at the Solar Energy Research Center of the University of Almeria in Spain. In order to improve the operation of the solar cooling and heating system of the Center, it was upgraded with two newly designed storage tanks filled with phase change materials (PCM). As a result of design works, commercial material S10 was selected for the accumulation of cold, and S46 for the accumulation of heat, in an amount of 85% and 15%, respectively. The article presents in detail the process of selecting the PCM material, designing the installation, experimental research, and exergy analysis. Individual tasks were carried out by research groups cooperating under the PCMSOL EUROPEAN PROJECT. Results of tests conducted on the constructed installation indicate that daily energy saving when using a solar chiller with PCM tanks amounts to 40% during the cooling season.

Açaí berry ( Euterpe precatoria ) and bataua ( Oenocarpus bataua ) are palms whose fruits are harvested in the Bolivian Amazon for pulp production, generating large volumes of seed residues that are currently discarded without further processing. This study presents a comparative physicochemical characterization of both seed types, evaluating their proximate composition, structural fractions (cellulose, hemicellulose, lignin), dietary fiber, lipids, proteins, and antioxidant properties. Characterization was performed following internationally recognized methods (AOAC, ISO, NB). Results confirmed a predominantly lignocellulosic matrix in both species, with total dietary fiber exceeding 84% on a dry basis. Açaí seeds exhibited higher cellulose content (51.44 ± 0.56% dry basis) and considerable antioxidant activity (IC ₅₀ = 4.56 ± 0.11 mg/mL by DPPH; TEAC = 4,975.68 ± 56.21 μmol TE/g), açaí seeds exhibited a high total phenolic content (3,565.95 ± 21.78 mg GAE/100 g), while bataua seeds showed a balanced cellulose–hemicellulose ratio (32.58 ± 0.15% and 31.89 ± 0.59%, respectively), high total phenolic content (797.25 mg GAE/100 g), and moderate antioxidant capacity (TEAC = 1,567.10 ± 16.10 μmol TE/g). A multi-criteria valorization matrix identified cellulose and antioxidant compounds as the priority fractions in both species, supporting an integrated extraction cascade. Alkaline extraction experiments using NaOH demonstrated effective delignification and cellulose enrichment, with temperature identified as the dominant factor controlling cellulose yield in bataua seeds. FTIR spectroscopy and polarized-light microscopy confirmed cellulose structural integrity and crystallinity in both species. The integrated valorization of these residues—antioxidant extraction followed by cellulose recovery from the remaining solid—is proposed as a circular-economy strategy aligned with sustainable bioeconomy principles and Bolivian environmental legislation for the Amazonian region.

The purpose of this research was to determine the technical feasibility of extracting amaranth seed oil with butane in a subcritical state and to take advantage of the cake generated. To this end, a type of non-germinated grain was characterized, oil was extracted from a germinated grain and the characterized one, the oil obtained was characterized, and the protein was extracted from the defatted cake of the non-germinated one. It was found that the non-germinated grain was made up of 13.33% protein, 7.24% fat, and 9.02% moisture, the optimum yield of this grain was 91%, for the germinated grain, a maximum value of 6.63% for oil mass. By comparing the characteristics of both oils, higher quality was found in the non-germinated oil, and the maximum protein extraction productivity was 5.15%. Thus, it has been concluded that this extraction method is technically feasible.

La Asociación Internacional de Mercados de Capitales (ICMA por sus siglas en inglés) desarrolló los Principios de los Bonos Verdes (GBP por sus siglas en inglés) que promueven un desarrollo integral del mercado de bonos verdes. Asimismo, la Iniciativa de Bonos Climáticos (CBI por sus siglas en inglés) ha introducido los criterios de Bonos Verdes para el sector de la energía hidroeléctrica. Los criterios para el componente mitigación es que las emisiones de gases de efecto invernadero deben estar debajo de 50 gramos de dióxido de carbono – equivalentes emitidos por kilovatio-hora– de energía eléctrica (g CO2eq kWh-1) para permitir una energía sostenible ambientalmente. Para acceder a un bono verde de un emisor local o internacional, los proyectos hidroeléctricos en Bolivia deben alinearse con los GPB, cumplir con los criterios de mitigación y adaptación del CBI y enmarcarse en las “Modificaciones del reglamento de mercados de valores bolivianos para bonos temáticos”.

Oenocarpus bataua Mart. (Arecaceae) (known as “majo” in Bolivia) is an Amazonian palm fruit with considerable potential for the development of functional foods; however, its rapid postharvest deterioration limits its utilization. This study evaluated the effects of preservation methods and frozen storage on the physicochemical properties of two morphotypes of its fruits (dark-purple and pale-colored). Proximate analysis of pulp and peel fractions revealed a lipid-rich composition, with crude lipid contents close to 49% (dry basis), moderate protein levels (7.1–9.7%), and crude fiber contents around 15%. Dietary fiber characterization showed exceptionally high total dietary fiber (61.6%), predominantly insoluble dietary fiber (56.3%) under short-term frozen storage. Fresh pulp exhibited high antioxidant capacity, as determined by the DPPH assay (2003–2070 µmol TE/g dry matter), while freeze-drying preserved significantly higher antioxidant activity than hot-air drying. Functional properties were strongly affected by storage duration, with water-holding capacity decreasing from (4.43–3.17) g H₂O/g dry matter and swelling capacity from 13.95 to 9.62 mL H₂O/g dry matter after prolonged freezing. FTIR spectroscopy confirmed the presence of characteristic polysaccharide and lignocellulosic structures and indicated structural disruption of the insoluble fiber matrix during long-term storage. These findings support the use of Bolivian majo as a promising source of functional ingredients and provide a basis for developing value-added Amazonian food products and optimizing preservation strategies.