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The Effectiveness of the Havriliak-Negami Model in Predicting the Master Curves of the Asphalt Blends with SBS Triblock Copolymer and Organic-Montmorillonite at Different Temperatures and Frequencies

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Journal of Materials Science and Chemical Engineering 2024年第7期12卷 23-39页

作者： María Ángeles Vargas-Hernández Miguel Ángel Vargas Pedro R. García-Morán Humberto Vázquez-Torres divisin de ingeniera qumica y bioqumica TecNMTecnolgico de Estudios Superiores de Ecatepec Edo. de Mxico Mxico Facultad de qumica Universidad Nacional Autonma de Mxico Cd. de Mxico Mxico Facultad de Ciencias Bsicas ingeniera y Tecnologa Universidad Autnoma de Tlaxcala Tlaxcala Mxico departamento de Fsica Universidad Autnoma Metropolitana-Iztapalapa Cd. de Mxico Mxico

The dynamic viscoelastic properties of asphalt AC-20 and its composites with Organic-Montmorillonite clay (OMMt) and SBS were modeled using the empirical Havriliak-Negami (HN) model, based on linear viscoelastic theory (LVE). The HN parameters, α, β, G0, G∞and τHN were determined by solving the HN equation across various temperatures and frequencies. The HN model successfully predicted the rheological behavior of the asphalt and its blends within the temperature range of 25˚C - 40˚C. However, deviations occurred between 40˚C - 75˚C, where the glass transition temperature Tg of the asphalt components and the SBS polymer are located, rendering the HN model ineffective for predicting the dynamic viscoelastic properties of composites containing OMMt under these conditions. yet, the prediction error of the HN model dropped to 2.28% - 2.81% for asphalt and its mixtures at 100˚C, a temperature exceeding the Tg values of both polymer and asphalt, where the mixtures exhibited a liquid-like behavior. The exponent α and the relaxation time increased with temperature across all systems. Incorporating OMMt clay into the asphalt blends significantly enhanced the relaxation dynamics of the resulting composites.

关键词： Asphalt Blends Master Curve Linear Viscoelasticity Havriliak-Negami Model

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Araucaria araucana Forests in Argentina: Exploring Floristic and Ecological Variability along a West-East Transect

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Open Journal of Forestry 2024年第4期14卷 433-450页

作者： Eduardo Martínez Carretero Ana Navas Romero Andrea Duplancic Marcela Ontivero Jorge Alcalá Jauregui Geobotnica y Fitogeografa (IADIZA-CONICET) Mendoza Argentina Instituto de ingeniera qumica Facultad de Ingeniera UNSJGrupo Vinculado Al PROBIEN (CONICET-UNCo) San Juan Argentina Facultad de Agronoma y Veterinaria Universidad Autnoma San Luis Potos San Luis Potos Mxico

In Argentina, the Araucaria araucana forest occupies a vast area in the Northwest of Patagonia, following a pronounced gradient of increasing xericity from west to east over a short distance. These forests have been the subject of detailed studies due to their uniqueness and ecological relevance. In this context, an exhaustive investigation was carried out to understand the diversity and structure of these ecosystems. The objective was to study the floristic and ecological differences in humid and xeric areas along a west-east transect where A. araucana is distributed. Floristic surveys, geomorphological analyses, and bioclimatic data were examined. In Argentina, A. araucana integrates two distinct forest types: mesic and xeric. The xeric A. araucana forest constitutes a forest with floristic, genetic, geomorphological, and bioclimatic identity. The results highlight the importance of understanding the local variability of these ecosystems for the design of effective conservation strategies. Furthermore, they highlight the need for further research into the ecology and dynamics of these forests, especially in the context of climate change and human activities.

关键词： Forest Floristic Identity Rocky Outcrops Xericity

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Allophane as a Nanotechnological Additive in Masonry Materials to Increase Resistance and Waterproofing

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Advances in Materials Physics and Chemistry 2024年第8期14卷 196-212页

作者： Edward H. Jiménez Joao Rivera Juan H. Villalba Paola E. Vera Marlon Cuenca Belén Granja Javier Fuentes Sandra Gavilanes Daniel Hidalgo Fernando Garcia Jose Bermudez Washington Ruiz Alexis Martial debut Facultad de ingeniera qumica Universidad Central del Ecuador Quito Ecuador Facultad de Arquitectura y Urbanismo Universidad Central del Ecuador Quito Ecuador Nanomaterials Characterization Laboratory Universidad de las Fuerzas Armadas ESPE Sangolqu Ecuador

The constant need for high-strength materials in the construction industry promotes the research of additives that improve the properties of masonry materials. The use of allophane as an additive in concrete and mortar mixtures was implemented to improve their strength and waterproofing, respectively, using compression and water absorption tests according to their corresponding standards (ASTM C1231, ASTM D2938, and ASTM C1585). The samples were evaluated at different concentrations and curing ages. In addition, different sand/cement ratios were considered for the mortar. The results revealed that there was a 9.4% increase in compressive strength in concrete and a 23.7% reduction in water absorption in mortar for the 5:1 ratio. These changes would be the result of the interaction of the nanoporous additive in the atomic crystal structure of the material demonstrating the nanotechnological nature of allophane.

关键词： Allophane Nano Additive Strength Impermeability Concrete Mortar

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Natural Numbers and the Strong Goldbach Conjecture

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Journal of Applied Mathematics and Physics 2024年第9期12卷 3208-3236页

作者： Ramon Carbó-Dorca Institut de qumica Computacional i Catalisi Universitat de Girona Girona Spain

This study introduces the representation of natural number sets as row vectors and pretends to offer a new perspective on the strong Goldbach conjecture. The natural numbers are restructured and expanded with the inclusion of the zero element as the source of a strong Goldbach conjecture reformulation. A prime Boolean vector is defined, pinpointing the positions of prime numbers within the odd number sequence. The natural unit primality is discussed in this context and transformed into a source of quantum-like indetermination. This approach allows for rephrasing the strong Goldbach conjecture, framed within a Boolean scalar product between the prime Boolean vector and its reverse. Throughout the discussion, other intriguing topics emerge and are thoroughly analyzed. A final description of two empirical algorithms is provided to prove the strong Goldbach conjecture.

关键词： Natural Numbers Prime Numbers Vector description of Natural Numbers Prime Boolean Vectors Primality of the Natural Unit Strong Goldbach’s Conjecture Vector Reversal Pairing Conjecture Natural Matrix Squeezing

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Accuracy Enhancement of the Folin-Ciocalteu Method for Propolis

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American Journal of Analytical Chemistry 2024年第8期15卷 253-267页

作者： Rosilene S. N. Paganotti Paulo J. S. Barbeira Instituto Federal de Educao Cincia e Tecnologia de Minas GeraisCampus Formiga Formiga MG Brazil departamento de qumica Instituto de Cincias Exatas Universidade Federal de Minas Gerais Belo Horizonte MG Brazil

This study presents an optimization of the Folin-Ciocalteu spectrophotometric method for the determination of total phenol content. Multivariate optimization using factorial planning 22 with a central point and central composite planning was constructed to evaluate the influence of variables in the process and maximize radiation absorption with minimal radiation scattering caused by solid formation. X-ray fluorescence and X-ray diffraction spectrometry were used to evaluate the chemical composition of solids formed and nephelometric and spectrophotometric studies were also used to evaluate whether the type, origin, dilution and dry extract contents of commercial propolis extracts would significantly influence the increase in radiation scattering and absorption. The optimized methodology added several advantages, such as reduction of reagents, time analysis, and higher accuracy.

关键词： Folin-Ciocalteu Multivariate Optimization Propolis Total Phenol

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Influence of the Extraction Process on the Characteristics of Romanian Mountain Walnut Oil

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American Journal of Plant Sciences 2024年第10期15卷 940-967页

作者： Anne-Gaëlle Gambert Sabina Niţu Andra Tămaș Maria Laura Fanani Justine Dupré Clara delepine Ludovic Chaveriat Patrick Martin Lucian Rusnac department of Chemistry University of Artois IUT Bthune Bthune France department of Applied Chemistry and Engineering of Organic and Natural Compounds Politehnica University Timisoara Timisoara Romania departamento de qumica Biolgica Ranwel Caputto Facultad de Ciencias Qumicas Universidad Nacional de Crdoba Crdoba Argentina Centro de Investigaciones en qumica Biolgica de Crdoba (CIQUIBIC) CONICET Crdoba Argentina Unit Transformations & AgroressourcesULR7519 University of Artois UniLaSalle Bthune France

The objective of this work is to extract walnut oil using various processes in order to compare the influence on the nature of the components extracted, and thus identify the areas of potential use. We carried out the extractions by mechanical process, thanks to a press in reduced model provided with a worm. We obtained cold extracted oil whose characteristics slightly diverge from extra virgin oil found in shops in Romania, but its composition is similar. We were also able to extract by chemical process using two methods, Folch and Soxhlet. Commercially available table walnut oils are only cold extracted to avoid the presence of solvents. Those are difficult to remove and strongly oxidize the oil. Currently, consumers appreciate walnut oil for its taste and nutritional qualities. In nutrition, this oil is put forward for its composition rich in polyunsaturated fatty acids, which are needed for human body. Food supplements made from walnut oil are available today. For the moment, this is the only use of walnut oil. Indeed, there are some studies on other fields of application, but they remain in the field of research and nothing has yet been commercialized. In this present study, we compared the chemical and physical properties of cold-extracted oil with the solvent extraction of walnut kernel originating from the mountain region of Rumania. The cold extracted oil has a high content of polyunsaturated fatty acids (63%) and monounsaturated fatty acids (30%), a very low level of saturated fatty acid (7%) and no content of linolenic acid. The Soxhlet and Folch methods produced slightly different oils with increased amounts of minor components, which changes their characteristic. Even when solvent-extracted oils do not meet the standard criteria imposed by the Codex Alimentarius, they offer a possible use in the fields of food, cosmetics industries and biomedicine.

关键词： Walnut Oil Extraction Composition Romanian Mountain

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