Comportamiento elástico de la madera. Teoría y aplicaciones

Saúl Antonio Hernández Maldonado (2010, [Tesis de maestría])

Facultad de Ingeniería en Tecnología de la Madera. Maestría en Ciencias en Tecnología de la Madera

The Thesis "Elastic behavior of wood. Theory and applications "is a contribution to the study of wood, modeled and analyzed, as a solid elastic, macroscopically homogeneous, with properties of a continuous medium and with orthoptic elastic and material symmetries. In the scientific and technological literature related to the mechanical characterization of wood, the current paradigm is to use, for purposes of conceptual analysis and research, a general theoretical model that explains the elastic behavior of wood. In Mexico, particularly in the context of Wood Technology Science and Engineering, there is no theoretical proposal, adapted to the conditions of the country that substantiates the results of research in this field. Likewise, it is difficult to locally identify a relevant proposal that explains the applications derived from the study of elastic behavior of wood. On the other hand, technological information on the mechanical response of wood of Mexican species lacks a theoretical, numerical and experimental conceptual framework that gives coherence to the data on the elastic characteristics of the national woods. From the above, it follows that research in Wood Science and the practice of Wood Technology Engineering require a Model that explains the elastic behavior of ligno-cellulosic matter. They also require useful experimental data in the design of structures and wood products. This problem can be seen from two perspectives: Scientific problem: The study of the elastic behavior of Mexican timber cannot be verified by the lack of an appropriate theoretical model. Technological and industrial problem: The design of structures and wood products in Mexico is deficient among other reasons, due to the lack of Engineering parameters and technological data to assure the reliability of the wood buildings and to improve the development of new products.

La Tesis “Comportamiento elástico de la madera. Teoría y aplicaciones” es una contribución al estudio de la madera, modelada y analizada, ésta como un sólido elástico, macroscópicamente homogéneo, con propiedades de un medio continuo y con simetrías materiales y elásticas ortotrópicas. En la literatura científica y tecnológica relacionada con la caracterización mecánica de la madera, el paradigma actual es emplear, para fines de análisis conceptual y de investigación, un Modelo teórico general que explique el comportamiento elástico de la madera. En México, particularmente en el contexto de Ciencias Tecnología e Ingeniería de la Madera, no existe una propuesta teórica, adaptada a las condiciones del País, que fundamente los resultados de investigación en este campo. Igualmente, es difícil identificar localmente una propuesta pertinente que explique las aplicaciones derivadas del estudio del comportamiento elástico de la madera. Por otra parte, la información tecnológica sobre la respuesta mecánica de la madera de especies mexicanas, carece de un marco conceptual teórico, numérico y experimental que dé coherencia a los datos sobre las características elásticas de las maderas nacionales. De lo anteriormente expuesto, se desprende que la investigación en Ciencias de la Madera y la práctica de la Ingeniería en Tecnología de la Madera, requieren de un Modelo que explique el comportamiento elástico de la materia ligno-celulósica. Igualmente, requieren datos experimentales útiles en el diseño de estructuras y productos de madera. Esta problemática se puede visualizar desde dos perspectivas: Problema científico: El estudio del comportamiento elástico de maderas mexicanas no puede ser verificable por la carencia de un Modelo teórico apropiado. Problema tecnológico e industrial: El diseño de estructuras y productos de madera en México es deficiente entre otras causas, por la falta de parámetros de Ingeniería y de datos tecnológicos para asegurar la confiabilidad de las edificaciones de madera y mejorar el desarrollo de nuevos productos.

INGENIERÍA Y TECNOLOGÍA FITECMA-M-2010-0006 Comportamiento Elasticidad Madera Teoría Aplicaciones

Selection indices for identifying heat tolerant of maize (Zea mays)

Pervez Zaidi (2023, [Artículo])

Stress Tolerance Indices Geometric Mean Productivity Stress Susceptibility Index Statistical Correlation CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CORRELATION HEAT STRESS ZEA MAYS DROUGHT STRESS BREEDING PROGRAMMES

Elaboración y evaluación de un tacón para tarimas a base de residuos de madera

Martin Parra Alcaraz (2019, [Tesis de maestría])

Facultad de Ingeniería en Tecnología de la Madera. Maestría en Ciencias en Tecnología de la Madera

The pallet is a product that allows us to move and transport products from the factory to the consumer. The wood-based pallet is the most demanded by its advantages over other materials, in terms of strength, weight and cost. However, in the manufacture of the block is used up to 20% of solid wood. Which generates environmental damage, causing difficulties in the supply and producing high manufacturing costs. An alternative is the use of wood waste in the manufacture of blocks. So in the present study, blocks were made from agglomerated wood waste with a resin-based adhesive with a range of 20% to 40%, with a density according to the NWPCA standard (National Wooden Pallet and Container Association). The blocks were evaluated in water absorption and dimentional change, lateral impact, extraction and insertion of nails. The elaborated blocks presented good characteristics to facilitate the insertion of nails. However, deficiencies in adhesion were detected in terms of water resistance and in terms of the strength of nail extraction. In the statistical analysis it was observed, that a higher percentage of adhesive higher is the lateral impact resistance, the insertion force and nail extraction; on the other hand, the water absorption and dimentional change decreased. And at increases the percentage of large particles, the water absorption and the dimensional change decrease

La tarima es un producto que nos permite mover y transportar productos de la fábrica al consumidor. La tarima de madera es la de mayor demanda por sus ventajas sobre otros materiales, en cuanto a resistencia, peso y costo. Sin embargo, en la fabricación de la tarima se utiliza hasta un 20% de madera sólida en la elaboración del tacón. Lo cual, genera un daño ambiental, provocando dificultades en el abastecimiento y produciendo altos costos de fabricación. Una alternativa, es el aprovechamiento de los residuos madereros en la fabricación de los tacones. Por lo que en el presente estudio, se elaboraron tacones a base de residuos de madera aglomeradas con un adhesivo a base de resinas con rango de 20% a 40%, con una densidad de acuerdo a la norma NWPCA (Asociación Nacional de Tarimas de Madera y Contenedores de Estados Unidos). Los tacones fueron evaluados en absorción de agua e hinchamiento, impacto lateral, extracción e inserción de clavos. Los tacones elaborados presentaron buenas características para facilitar la inserción de clavo. Sin embargo, se detectaron deficiencias del adhesivo en cuanto a resistencia al agua y en cuanto a la resistencia de extracción de clavos. Con el análisis estadístico se observó, que a mayor porcentaje de adhesivo, la resistencia al impacto lateral, la fuerza de inserción y extracción de clavos aumento; por otro lado, la absorción de agua y el hinchamiento disminuyo. Y Al aumentar el porcentaje de partículas grandes, disminuyo la absorción de agua y el cambio dimensional.

INGENIERÍA Y TECNOLOGÍA FITECMA-M-2019-0223 Aglomerado Clavos Propiedades físico-mecánicas

Estudio etnofarmacológico y fitoquímico de las plantas medicinales de mayor uso en Julián Blanco, Guerrero, México

SAMUEL CONDORI CORDERO DAVID OSVALDO SALINAS SANCHEZ (2022, [Artículo])

El uso de plantas medicinales para tratar diversas enfermedades se ha visto fuertemente impulsado por el aumento del costo de los medicamentos y los efectos secundarios de éstos. Así, en países en vías de desarrollo, el uso de plantas medicinales se ha vuelto cada vez más importante en la atención primaria de la salud. En este artículo, se describen las especies vegetales que los habitantes de Julián Blanco, Guerrero, México, utilizan frecuentemente para el tratamiento de sus enfermedades. La información sobre nombres comunes, partes usadas y métodos de preparación fue obtenida a través de la aplicación de una encuesta mixta a 100 personas de la localidad. Se reporta un total de 74 especies pertenecientes a 35 familias y 69 géneros. Las especies vegetales con mayor porcentaje de mención fueron: Ceiba aesculifolia (Kunth) Britten & Baker f. (Malvaceae) (23%), Aristolochia tentaculata O.C.Schmidt (Aristolochiaceae) (12%), Lippia alba (Mill.) N.E.Br. ex Britton & P.Wilson (Verbenaceae) (12%), Senna alata (L.) Roxb. (Fabaceae) (12%) y Heterotheca inuloides Cav. ex Sosa & Gómez (Astaraceae) (10%). Mediante pruebas fitoquímicas clásicas, se registró que las especies de mayor uso contienen alcaloides, terpenos, flavonoides, cumarinas y triterpenos. Además, se llevó a cabo un análisis de cromatografía de gases masas (CG-MS) a C. aesculifolia, la especie vegetal de mayor mención, y se identificó el alcano nonacosano como compuesto mayoritario. Estos resultados indican que existe una gran variedad de especies vegetales y un conocimiento valioso para combatir las enfermedades.

The use of medicinal plants to treat various diseases is strongly encouraged by the increase in

drug costs and their side effects. In underdeveloped countries, it has become increasingly important in primary health care. This work describes the plant species frequently used by the inhabitants of Julián Blanco, Guerrero, Mexico, for the treatment of their diseases. The information on common names, parts of the plants and preparation methods was obtained through a mixed survey of 100 people from the locality. A total of 74 species belonging to 35 families and 69 genera are reported. The plant species with the highest percentage of mentions were: Ceiba aesculifolia (Kunth) Britten & Baker f. (Malvaceae) (23%), Aristolochia tentaculate O.C.Schmidt (Aristolochiaceae) (12%), Lippia alba (Mill.) N.E.Br. ex Britton & P. Wilson (Verbenaceae) (12%), Senna alata (L.) Roxb. (Fabaceae) (12%) and Heterotheca inuloides Cav. ex Sosa & Gómez (Astaraceae) (10%). Classical phytochemical tests recorded that the most popular species contain alkaloids, terpenes, flavonoids, coumarins, and triterpenes. In addition, a mass gas chromatography (GC-MS) analysis was performed on C. aesculifolia, the most frequently mentioned plant species. The alkane nonacosane was identified as the main compound. These results indicate that there is a great variety of plant species and valuable knowledge to combat diseases.

BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA Plantas medicinales, conocimiento tradicional, enfermedades, estudio fitoquímico.

Addressing agricultural labour issues is key to biodiversity-smart farming

Thomas Daum Frédéric Baudron Matin Qaim Ingo Grass (2023, [Artículo])

There is an urgent need for agricultural development strategies that reconcile agricultural production and biodiversity conservation. This is especially true in the Global South where population growth is rapid and much of the world's remaining biodiversity is located. Combining conceptual thoughts with empirical insights from case studies in Indonesia and Ethiopia, we argue that such strategies will have to pay more attention to agricultural labour dynamics. Farmers have a strong motivation to reduce the heavy toil associated with farming by adopting technologies that save labour but can negatively affect biodiversity. Labour constraints can also prevent farmers from adopting technologies that improve biodiversity but increase labour intensity. Without explicitly accounting for labour issues, conservation efforts can hardly be successful. We hence highlight the need for biodiversity-smart agriculture, that is farming practices or systems that reconcile biodiversity with land and labour productivity. Our empirical insights suggest that technological and institutional options to reconcile farmers' socio-economic goals and biodiversity conservation exist but that more needs to be done to implement such options at scale.

Land Sharing Trade-Offs CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA AGRICULTURAL DEVELOPMENT BIODIVERSITY CONSERVATION LABOUR SUSTAINABILITY

Plastificado higro-térmico de la madera de Quercus scytophylla. Estudio por ondas de esfuerzo

Joel Benancio Olguín Cerón (2011, [Tesis de maestría])

Facultad de Ingeniería en Tecnología de la Madera. Maestría en Ciencias en Tecnología de la Madera

Wood is a thermoelastic material: when the internal temperature of the wood increases, its modulus of elasticity decreases. This manifestation has an instantaneous and temporary character. That is, if the wood recovers its initial temperature, the modulus of elasticity regains its previous value. This is preferably observed in a temperature range of 0 to 120 ° C.

La madera es un material termoelástico: cuando la temperatura interna de la madera aumenta, su módulo de elasticidad disminuye. Esta manifestación tiene un carácter instantáneo y temporal. Es decir, si la madera recobra su temperatura inicial, el módulo de elasticidad recobra su valor anterior. Este hecho se observa preferentemente en un rango de temperaturas de 0 a 120 °C.

INGENIERÍA Y TECNOLOGÍA FITECMA-M-2011-0003 Plastificado Hogro-térmico Madera Quercus scytophylla Ondas

Influencia de las fases lunares en fertilidad, tasa de preñez y partos de vacas mestizas en el trópico seco.

CANUTO MUÑOZ GARCIA ROSENDO CUICAS HUERTA JUAN GONZALEZ MALDONADO EFREN ESTRADA PAQUI ISIDRO JAUREGUI PLATA JULIO CESAR GOMEZ VARGAS (2023, [Artículo])

There is speculation about moon phases influencing animal reproductive performance. A study was carried out to shed light on the influence of moon phases on estrus presentation, pregnancy rate, calving presentation, and offspring sex in cows from the Mexican dry tropical region. The reproductive data of 580 crossbred cows from 2010 to 2021 was organized according to reproductive events (estrus presentation, gestation, calving presentation, and offspring sex) occurrence during moon phases (new moon, first quarter, full moon, and last quarter). The data were analyzed by Chi-squared test and logistic regression. The full moon reduced the estrus presentation (p0.05). It is concluded that the full moon reduces estrus presentation in crossbred cows. Moon phases do not influence the gestation, calving presentation, and offspring sex.

estrus calving offspring sex CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS CIENCIAS VETERINARIAS FISIOLOGÍA ANIMAL

Análisis de las conexiones matemáticas en la enseñanza y aprendizaje de la derivada basado en un networking of theories entre la Teoría de las conexiones y el Enfoque ontosemiótico.

CAMILO ANDRES RODRIGUEZ NIETO (2021, [Tesis de doctorado])

Consejo Nacional de Ciencia y Tecnología No. 602990

In research in Mathematics Education, models have been reported to analyze mathematical connections in which specific connection categories are considered. In the literature, it was identified that the most used model is the Businskas with contributions from other researchers. However, the problem refers to the fact that some categories of connections limit the analysis of mathematical activity and, therefore, the research suggests that the established categories are validated and, if possible, new categories of connections are reported. Other investigations focused on exploring mathematical connections and understanding the derivative reveal that high school students, pre-service teachers, and some in-service mathematics teachers have difficulty connecting multiple representations of the derivative (e.g., algebraic, or symbolic, verbal, graphic, tabular) and establish connections between partial meanings about this concept.

Networking of theories Mathematical connections Onto-semiotic approach semiotic function derivative teacher students HUMANIDADES Y CIENCIAS DE LA CONDUCTA PEDAGOGÍA TEORÍA Y MÉTODOS EDUCATIVOS TEORÍAS EDUCATIVAS

Gender analysis of household seed security : A case of maize and wheat seed systems in Nepal

Hom Nath Gartaula (2022, [Libro])

Seed Security Mountains CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA SEED SYSTEMS MAIZE WHEAT ROLE OF WOMEN WOMEN'S PARTICIPATION

Intimate partner violence and its relationship to labor income

Yei Javier Zepeda Hernández Alma Sofia Santillan (2024, [Artículo, Artículo])

In Mexico, 70.1% of women have been victims of violence in their lifetime and the main perpetrator is her intimate partner. Gender violence is a public health problem that has multiple negative impacts in woman and their offsprings. The relation violence and income is an issue that has been scarcely studied for Mexico. The objective of this article is to analyze the intimate partner violence and its relationship to labor income for Mexican women, data used are from the National Survey on the Dynamics of Households Relationships (ENDIREH 2021). The principal component method is used to estimate five kinds of violence; physical, emotional, economic, sexual and, harassment. The instrumental variables method is used to consider the endogeneity of income and violence variables. Except harassment, the results indicate a negative relationship between income and violence. Specifically, sexual violence has the greatest negative effects; women who are victims of sexual violence have an average reduction of 17.4% in monthly labor income. This negative effect represents a loss of just over two month of working days per year and, in the aggregate terms, is equivalent to 0.87% of GDP. The above highlights the importance of orienting public policy actions to work in prevention, attention, punishment and eradications any kind of violence against women. 

Intimate partner violence Labor income Endogeneity Instrumental variables Cost of violence Violencia de pareja Ingresos laborales Endogeneidad Variables instrumentales Costo de la violencia. CIENCIAS SOCIALES CIENCIAS SOCIALES