Quantifying asphalt emulsion-based chip seal curing times using electrical resistance measurements

Chip seals are among the most cost-effective surface treatments available for asphalt pavement preventive maintenance. Chip sealing typically consists of covering a pavement surface with asphalt emulsion into which aggregate chips are embedded. The asphalt emulsion cures through the evaporation of water, which helps to provide mechanical strength for the chip seal. Ultimately, the curing process enables the emulsion to adhere to the pavement while keeping the aggregate chips in place. The curing time for the chip seal depends on many factors, such as the asphalt emulsion and aggregate types, aggregate moisture content, emulsion and aggregate application rates, and environmental conditions (e.g., temperature, wind speed, relative humidity, and solar radiation). Currently, no field technique is available that can quantify when sufficient mechanical strength has developed in the binder to allow traffic on a newly sealed roadway or to remove the surplus aggregate from a fresh chip seal. Such decisions are made by empirical factors that rely on the experience of field personnel. Consequently, frequent problems associated with the lack of early mechanical strength development of asphalt emulsion, which can result in premature surface treatment failure, have led to the need to improve the characterization of the chip seal curing process. As such, this study investigated the use of an electrical resistance measurement to develop a sound construction methodology to prevent common failures that occur soon after construction. First, full frequency, two-point, uniaxial electrical impedance spectroscopy was used to characterize the electrical properties of asphalt emulsions and various asphalt emulsion-aggregate combinations. The laboratory test results suggest a relationship between the changes in the electrical resistance of an asphalt emulsion and the amount of curing that has occurred in a chip seal system. In addition, standardized mechanical strength tests and full-scale field trials were conducted using a variety of materials. The electrical properties of the fresh seal coats were quantified by employing a handheld electrical device with a two-point probe to measure resistance. The findings suggest that chip seal systems gain significant mechanical strength when the initial electrical resistance measurement increases by a factor of 10. Finally, the implementation of the methodology for five full-scale chip seal systems in Indiana indicates that curing times for the chip seal projects range from 3.5 to 4.0 hours. Electrical resistance measurements can provide a rapid, nondestructive, low-cost indication of the amount of curing that has occurred in a chip seal. The application of this methodology will result in more accurate, robust, and timely decisions with regard to when a chip seal has gained sufficient mechanical strength to allow brooming or opening to unrestricted traffic without undue loss of cover aggregate. Furthermore, implementing this construction technique could positively impact chip seal construction quality as well as extend the service life of the chip seal. Lastly, the findings of this study can be extended to include a variety of asphalt emulsion applications

Self-Regulation of SMR Power Led to an Enhancement of Functional Connectivity of Somatomotor Cortices in Fibromyalgia Patients

Neuroimaging studies have demonstrated that altered activity in somatosensory and motor cortices play a key role in pain chronification. Neurofeedback training of sensorimotor rhythm (SMR) is a tool which allow individuals to self-modulate their brain activity and to produce significant changes over somatomotor brain areas. Several studies have further shown that neurofeedback training may reduce pain and other pain-related symptoms in chronic pain patients. The goal of the present study was to analyze changes in SMR power and brain functional connectivity of the somatosensory and motor cortices elicited by neurofeedback task designed to both synchronize and desynchronize the SMR power over motor and somatosensory areas in fibromyalgia patients. Seventeen patients were randomly assigned to the SMR training (n = 9) or to a sham protocol (n = 8). All participants were trained during 6 sessions, and fMRI and EEG power elicited by synchronization and desynchronization trials were analyzed. In the SMR training group, four patients achieved the objective of SMR modulation in more than 70% of the trials from the second training session (good responders), while five patients performed the task at the chance level (bad responders). Good responders to the neurofeedback training significantly reduced pain and increased both SMR power modulationandfunctionalconnectivityofmotorandsomatosensoryrelatedareasduring the last neurofeedback training session, whereas no changes in brain activity or pain were observed in bad responders or participants in the sham group. In addition, we observed that good responders were characterized by reduced impact of fibromyalgia and pain symptoms, as well as by increased levels of health-related quality of life during the pre-training sessions. In summary, the present study revealed that neurofeedback training of SMR elicited significant brain changes in somatomotor areas leading to a significant reduction of pain in fibromyalgia patients. In this sense, our research provide evidence that neurofeedback training is a promising tool for a better understanding of brain mechanisms involved in pain chronification

Ley general de aguas, la amenaza que se desechó... por ahora

Texto que celebra con cautela el triunfo ante la clase política mexicana, tras el intento fallido de mercantilizar el agua. Se exponen las razones por las que el dictamen de la Ley General de Aguas vulneraba el derecho humano al acceso al líquido y su saneamiento, y se explica por qué la iniciativa favorecía el interés particular para su gestión frente al interés público y social.ITESO, A.C

Plan de negocio Proyecto Agroecoturístico vereda Samaria municipio de Villahermosa - Tolima

141 páginas : ilustraciones, gráficasEste proyecto contempla un plan de negocio para la puesta en marcha de un espacio agro-ecoturístico ubicado en la vereda samaria del municipio de Villahermosa – Tolima que ofrece como producto principal el cultivo y distribución de Trucha Arcoíris y como servicios complementarios espacios naturales para la recreación y entretenimiento en torno a la naturaleza (ecoturismo). El plan de negocio se construyó, mediante el desarrollo de los siguientes aspectos: 1) Recopilación de información sobre el estado del sector piscícola en Colombia y la región de américa, la selección de aspectos macroeconómicos y del sector con el fin de analizar cómo estos podrían impactar el proyecto y ser por tanto una amenaza por mitigar o una oportunidad a potenciar. Adicionalmente se analizó el estado y proyección de Colombia en cuanto al sector agro ecoturístico para conocer las tendencias, realidad y posibles servicios y espacios a incluir dentro del plan de negocio. 2) Se realizó un estudio de mercado que consistió de visitas al sitio para indagar sobre la realidad del espacio físico destino de este plan y su entorno. Adicionalmente se realizaron encuestas a los pobladores del municipio con el fin de contar con la información necesaria para así definir las características de los productos que serían ofrecidos en el sitio, así como sus formas de distribución, promoción y precio. 3) De acuerdo a la capacidad de producción se realizó el estudio técnico que permitió definir la infraestructura requerida para llegar a una meta máxima de producción de Trucha de 1 tonelada mensual. 4) Se definió la empresa y sus características administrativas, esto es su misión, su visión, su imagen, sus principios, competencias y objetivos, así como la estructura organizacional, y el personal requerido para la puesta en marcha del plan de negocio y coma tal de la empresa. 5). Se proyecto un pronóstico de ventas a 6 años, con escenarios muy pesimistas, y muy optimistas con el fin de obtener valores de los ingresos, se definió el valor de la inversión en cuanto a requerimientos de infraestructura, equipos, suministros, con el fin de realizar un análisis financiero y obtener la tasa interna de retorno para evaluar la factibilidad de la ejecución del plan de negocio. Cómo parte final se revisaron todos los requerimientos legales para la constitución de la empresa, las empresas que rigen el sector piscícola como de turismo. y todas las restricciones y proyecciones del plan de ordenamiento territorial del municipio de Villahermosa, así como la documentación de la finca elegida para el proyecto.Se pudo concluir que es un proyecto innovador, que traería no sólo beneficios a los emprendedores de éste sino desarrollo económico y social al municipio de Villahermosa, sus alrededores y por tanto al país.This project includes a business plan for the start-up of an agro-ecotourism space located in the village of Villahermosa - Tolima, which offers as a main product the cultivation and distribution of Rainbow Trout and as complementary services, natural spaces for recreation. and entertainment around nature (ecotourism). The business plan was built, through the development of the following aspects: 1) Compilation of information on the state of the fish sector in Colombia and the region of America, the selection of macroeconomic and sector aspects in order to analyze how these could impact the project and therefore be a threat to mitigate or an opportunity to enhance. Additionally, the state and projection of Colombia in the agro-ecotourism sector was analyzed to know the trends, reality and possible services and spaces to be included in the business plan. 2) A market study was carried out that consisted of visits to the site to inquire about the reality of the physical space destined for this plan and its environment. Additionally, surveys were carried out to the inhabitants of the municipality in order to have the necessary information to define the characteristics of the products that would be offered on the site, as well as their distribution, promotion and price. 3) According to the production capacity, the technical study was carried out that allowed us to define the infrastructure required to reach a maximum goal of Trout production of 1 ton per month. 4) The company and its administrative characteristics were defined, this is its mission, its vision, its image, its principles, competencies and objectives, as well as the organizational structure, and the personnel required for the implementation of the business plan and comma such of the company. 5). A 6-year sales forecast was planned, with very pessimistic scenarios, and very optimistic in order to obtain income values, the value of the investment was defined in terms of infrastructure, equipment and supplies requirements, in order to perform a financial analysis and obtain the internal rate of return to evaluate the feasibility of executing the business plan. As a final part, all the legal requirements for the constitution of the company, the companies that govern the fish sector and tourism were reviewed. and all the restrictions and projections of the land management plan of the municipality of Villahermosa, as well as the documentation of the farm chosen for the project It was possible to conclude that it is an innovative project, which would bring not only benefits to the entrepreneurs of this but economic and social development to the municipality of Villahermosa, its surroundings and therefore to the country.Incluye bibliografíaPregradoMédico(a) Veterinario Zootecnist

Quantifying Asphalt Emulsion-Based Chip Seal Curing Times Using Electrical Resistance Measurements

Chip sealing typically consists of covering a pavement surface with asphalt emulsion into which aggregate chips are embedded. The asphalt emulsion cures through the evaporation of water, thus providing mechanical strength to adhere to the pavement while keeping the aggregate chips in place. The curing time for the chip seal depends on many factors, such as the asphalt emulsion and aggregate types, aggregate moisture content, emulsion and aggregate application rates, and environmental conditions (e.g., temperature, wind speed, relative humidity, and solar radiation). Currently, no field technique is available to quantify when sufficient mechanical strength has developed in the binder to allow traffic on a newly sealed roadway or to remove the surplus aggregate from a fresh chip seal through brooming. Instead such decisions are made by empirical factors that rely on the experience of field personnel. This study investigated the use of electrical resistance measurements to develop a quantitative method for determining the optimum curing time for chip seals. First, full frequency, two-point, uniaxial electrical impedance spectroscopy was used to characterize the electrical properties of asphalt emulsions and various asphalt emulsion-aggregate combinations. The laboratory test results suggest a relationship between the changes in the electrical resistance of an asphalt emulsion and the amount of curing that has occurred in the system. Additionally, standardized mechanical strength tests and full-scale field trials were conducted using a variety of materials. The electrical properties of the fresh seals were quantified using a handheld electrical device with a two-point probe to measure resistance. The findings suggest that chip seal systems gain significant mechanical strength when the initial electrical resistance measurement increases by a factor of 10. Finally, the implementation of the methodology for five full-scale chip seal projects in Indiana indicates that curing times for the chip seals range from 3.5 to 4.0 hours

El efecto estratégico de la colaboración entre ETICS

This paper analyzes the relationship between networking capabilities and the motives behind SMEs taking part in collaborative relationships with firms within the same sector. Specifically, we analyzed inter-firm collaborations for new product development and the decision(s) to outsource. The main contribution of this paper is focused on identifying the existence of the mediating effect that Hybrid growth strategy has, connected to these relations. It is argued that the Hybrid growth strategy mediates the relationship between networking capabilities and the different collaborative modes with firms within the same sector. The results, obtained through a binomial logit model, supported these arguments by using a database formed by 450 face-to-face surveys, from which 296 took part in an inter-firm collaboration between 2012-2014. The surveys were given to CEOs from SMEs that participated in collaborative activities with other firms in the Electronic, Technology, Information, and Communications sector (ETICS) in Mexico.El presente artículo analiza la relación entre las capacidades relacionales y los motivos de las PYMEs, que establecen relaciones de colaboración con empresas del mismo sector. Específicamente, analizamos las colaboraciones entre empresas para el desarrollo de nuevos productos y las decisiones de subcontratar. La principal contribución del artículo se centra en identificar la existencia del efecto mediador que tiene la estrategia de crecimiento híbrida, entre estas relaciones. Se argumenta que la estrategia de crecimiento híbrido media la relación entre las capacidades relacionales y los diferentes motivos de colaboración con empresas dentro del mismo sector. Los resultados, obtenidos a través de un modelo logit binomial, respaldaron estos argumentos mediante el uso de una base de datos formada por 450 encuestas realizadas cara a cara, de las cuales 296 participaron en una colaboración entre empresas entre 2012 y 2014. Las encuestas fueron realizadas a CEOs de PYMEs que participaron en actividades de colaboración con otras empresas del sector de Electrónica, Tecnología, Información y Comunicaciones (ETICS) en México

Firm Capabilities and Growth Strategies: The Moderating Role of Institutional Factors

Building on Resource-Based View (RBV) and Institutional Theory (IT), we decided to study the internal and external factors that affect the choice between different growth strategies in small and medium enterprises (SMEs) in an emerging economy. We started identifying that there is a direct relationship betweentechnological resources and an organic growth strategy, financial resources and an acquisitive growth strategy, and networking capabilities and a hybrid growth strategy. We argue that the intensity of these relations is moderated by institutional factors, such as a country’s intellectual property protections (for organic strategies), credit access (for acquisitive strategies), and trust in the business environment (for hybrid strategies). We based our findings on 450 face-to-face surveys with CEOs from firms in the Electronic Technology, Information, and Communication Sector (ETICS) in Mexico. Managerial implications are also discussed in the paper, as well as future avenues of research.Empleando los principios de la Teoría de Recursos y Capacidades (RBV) y de la Teoría Institucional (IT), decidimos estudiar los factores internos y externos que afectan la elección entre diferentes estrategias de crecimiento en empresas pequeñas y medianas (Pymes) en una economía emergente. Iniciamos identificando que hay una relación directa entre recursos tecnológicos y una estrategia de crecimiento orgánico, recursos financieros y una estrategia de crecimiento por adquisiciones, y capacidades relacionales y una estrategia de crecimiento híbrida. Argumentamos que la intensidad de estas relaciones es moderada por factores institucionales del entorno, como la protección de un país sobre la propiedad intelectual (para estrategias orgánicas), acceso al crédito (para estrategias de adquisición), y confianza en el ambiente empresarial (para estrategias híbridas). Basamos nuestros descubrimientos en 450 encuestas cara a cara con directores de empresas en el sector de tecnología electrónica, información y comunicación (ETICS) en México. En este artículo también se discuten implicaciones gerenciales, así como futuras líneas de investigación

Effect of bi- and trimodal size distribution on the superficial hardness of Al/SiCp composites prepared by pressureless infiltration

The effect of particle size distribution on the superficial hardness of Al/SiCp composites prepared by pressureless infiltration, as well as on the microhardness and fracture toughness (KIC) of particulate silicon carbide (SiCp) was investigated. Preforms with 0.6 volume fraction of SiC powders (10, 68 and 140 μm) with monomodal, bimodal and trimodal distribution were infiltrated with the alloy Al–15.52 Mg–13.62 Si (wt.%) in argon followed by nitrogen at 1100 °C for 60 min. Results show that density behaves linearly with increase in particle-size-distribution whilst superficial hardness, microhardness and fracture toughness exhibit all a parabolic behavior. Superficial hardness behavior can be explained by the combined effect of work-hardening in the alloy matrix and particle-to-particle impingement. Due to the highly covalent nature of SiC, the parabolic response shown by microhardness and KIC cannot be attributed to a dislocation mechanism as in strain-hardening.The effect of particle size distribution on the superficial hardness of Al/SiCp composites prepared by pressureless infiltration, as well as on the microhardness and fracture toughness (KIC) of particulate silicon carbide (SiCp) was investigated. Preforms with 0.6 volume fraction of SiC powders (10, 68 and 140 μm) with monomodal, bimodal and trimodal distribution were infiltrated with the alloy Al–15.52 Mg–13.62 Si (wt.%) in argon followed by nitrogen at 1100 °C for 60 min. Results show that density behaves linearly with increase in particle-size-distribution whilst superficial hardness, microhardness and fracture toughness exhibit all a parabolic behavior. Superficial hardness behavior can be explained by the combined effect of work-hardening in the alloy matrix and particle-to-particle impingement. Due to the highly covalent nature of SiC, the parabolic response shown by microhardness and KIC cannot be attributed to a dislocation mechanism as in strain-hardening

Effect of SiCp multimodal distribution on pitting behavior of Al/SiCp composites prepared by reactive infiltration

The effect of coated-SiCp multimodal-size-distribution on the pitting behavior of Al/SiCp composites was inves- tigated. α-SiC powders (10, 54, 86, and 146 μm) were properly mixed and coated with silica to produce porous preforms with 0.6 volume fraction of the reinforcement with monomodal, bimodal, trimodal, and cuatrimodal size distribution. The preforms were infiltrated with the alloy Al–13 Mg–1.8Si (wt.%) in argon followed by nitrogen at 1100 oC for 60 min. The composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) before and after cyclic polarization measurements in 0.1 M NaCl de-aerated solu- tions. Results show that whereas corrosion and passivation potentials are not influenced with increase in SiCp particle size distribution, favorably, the susceptibility to pitting corrosion decreases. This beneficial effect is ascribed to the smaller area of the alloy matrix exposed to the chloride solution with augment in particle size distribution, substantially when going from monomodal to bimodal SiCp particle size distribution