bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development and characterization of a polymer based on the biomimicry of the intervertebral disc
Authors: Angulo K P , Villegas D F , Ramírez G E 
Published: November 2019

Abstract
The development and characterization of a functional graded composite material based on the biomimicry of the human intervertebral disc is reported in this research. The material consists of concentric radial polyurethane layers, synthesized using a condensation polymerization chemical reaction, found on methylene diphenyl diisocyanate, glycerol and castor oil as reagents. The proportions in the components of the polyol, glycerol and castor oil, were modified to generate a change in the degrees of cross-linking in the chains of the material, resulting in slightly rigid layers, as in the structure of the intervertebral disc. Two radial gradations were made through a rotating assembly and the complex modulus of the constituent polyurethane layers was used as the gradation criteria since the complex modulus provides a general description of the mechanical behaviour. After the gradation process, the graded material was characterized by means of a dynamic mechanical analysis that determines its viscoelastic properties, like storage modulus, loss modulus, complex modulus and tan δ. Moreover, with its behavioural pattern to compression and flexion, we performed a comparative analysis of the improvement of the mechanical properties of its constituent materials. The development of this study under biomechanical and chemical guidelines came together with two proposals of graded materials with high versatility and functionality in terms of frugality and stability for temperatures changes, as well as absorption and dissipation of mechanical energy. Furthermore, it serves as a tool for the elaboration of machines elements under combined load of compression and flexion at a low cost.
Determination of correlation of compressive strength with maturity of concrete mixed with accelerator
Authors: Medrano C T , Peña-Rodríguez G , García-Páez I H 
Published: November 2019

Abstract
The compressive strength of concrete mixtures with accelerator additives designed for structural elements with strength of 5000 psi was correlated with the maturity index of concrete at an early age. The design of the mixture was made by adding the quantity of additives according to the specifications of the supplier. The maturity index was calculated using the thermal profile of the concrete dependent of the setting time, which was obtained through an automated adiabatic system. The number of thermal sensors required for temperature measurement dependent of setting time (1, 3, 7, 14 and 28 days) was determined by a factorial experimental design of two factors. The correlation coefficient was 0.96, so the logarithmic model adequately explains the variability of the compressive strength. The equation obtained was validated by means of the values of resistance to compression measured by the standard method for each age of the concrete; all values are within the calibration range of the resistances estimated by the maturity method.
Vitrification of the solid waste obtained from the vacuum crushing of fluorescent lamps: chemical analysis and determination of the chemical stability in water of the vitrified solids
Authors: Amaya-Manjarrés G , Jiménez-Martínez J , Delvasto P 
Published: November 2019

Abstract
This paper deals with the vitrification processing of the wastes of glass and phosphor powder obtained after the vacuum crushing of spent fluorescent lamps. Both materials were characterized by means of scanning electron microscopy and X-ray fluorescence chemical analysis. The vitrification tests were performed at 1,100°C and 20 wt % borax was added to the samples as fluxing aid. Four formulations (batches) of glasses were made, the first one consisted only of spent lamp glass, the second one of spent lamp glass plus borax, the third one was the same as the second, but incorporating 20% weight of spent phosphor powder. The fourth one, a control, was made combining soda-lime glass cullet and borax. All four batches were chemically analyzed by X-ray fluorescence and no Hg was found on them. Rare earth elements were detected in the third batch glass prepared. The chemical stability of all batches was tested by contacting tests of the glasses with distilled water. As indicative of the stability, pH and electrical conductivity of the supernatants was measured. It was found that the more stable glasses were those incorporating only borax and spent lamp glass.
Mechanical strength of experimental mortars for plastering with partial addition of fly ash and hydrated lime
Authors: Hurtado-Figueroa O , Vega-Vanegas EJ , Cárdenas-Gutiérrez JA 
Published: November 2019

Abstract
In order to highlight the implementation of fly ash and hydrated lime in replacement of a % of the weight of the cementitious material traditionally used for the elaboration of mortar mixtures, a conventional mixture was made for mortars where the materials that compose this type of mixtures were previously selected, analyzed and implemented. The evaluations of the materials were carried out under the standards indicated by the Norma Técnica Colombiana that guarantee the reliability of the resulting mixture. The fly ash that was used was obtained from the power plant Termotasajero of the Municipality of San Cayetano located in the department of north Santander-Colombia. The hydrated lime was obtained in the municipality of Malaga located in the department of Santander-Colombia. The experimental mixtures presented a replacement of 40%, 50%, 60% and 70% of the weight of the cementitious material traditionally used in the city. At the same time, 10%, 20% and 30% of hydrated lime was added to the experimental mixtures in relation to the weight of the added fly ash. With each one of the elaborated mixtures, both traditional and experimental, 3 cubes were made as indicated in the Norma Técnica Colombiana for this purpose. After the 21 days of its elaboration to each one of the cubes their resistance to compression was determined by means of their respective test in the ibertest machine property of the Francisco de Paula Santander university located in the city of San Jose de Cucuta-Colombia. The data obtained in the tests were compared determining the viability of the addition of fly ash and hydrated lime in the mixtures for paste mortar, with the incorporation of a %. additional water in their designs. Thus generating a positive environmental, social and economic impact through the final disposal and marketing of an industrial waste, fly ash, and the use of a natural material, hydrated lime, in mixtures with cementitious matrix for mortars.
Comparative study of the effect of the exchange-correlation functional on the structural and electronic properties of rutile
Authors: Bolívar Marín Y , Alcalá Varilla L A , González Ramirez I A 
Published: November 2019

Abstract
A comparative study is presented, based on density functional theory, of the influence that the different approximations of the exchange-correlation functional have on the structural and electronic properties of titanium dioxide in the rutile phase. In this work, the method of plane waves and pseudopotentials, as implemented in the Quantum Espresso package was used. The approximations to the exchange-correlation functional that were considered are the local density approximation, the generalized gradient approximation in the form of Perdew- Burke-Ernzerhof, the Perdew-Burke-Ernzerhof for solids, and the Perdew-Wang 91. For each case, the effects due to the inclusion of spin (spin polarization), and the correction of Hubbard (U = 4.2 eV for Ti) were also studied. We found that the Perdew-Burke-Ernzerhof for solids functional offers the best results for the calculation of the lattice parameters and bond lengths, followed by the Perdew-Burke-Ernzerhof and Perdew-Wang 91. For the bond angles, the best description was obtained with the Perdew-Burke-Ernzerhof and Perdew-Wang 91 approximations. The density analysis of states showed that the functional PW91 and PBE, better describe the band gap compared with the functional PBEsol and LDA when the Hubbard correction it is not been included, however, when this is included all the functional show the same deviation with respect to the experimental value (E
gap
= 3.0 eV). With and without the Hubbard correction (U = 4.2), all functionals underestimate the band gap.
Effect of expanded polystyrene waste in the creation of waterproofing paint
Authors: Bellon D , Zamudio W H , Tiria L C , Durán S M , Useche I E , Peña J 
Published: November 2019

Abstract
The production, use, and poor management of polymers, and especially of expanded polystyrene, have resulted in various environmental challenges, such as large-scale waste generation, accumulation of toxic substances, and the pollution of natural resources, chiefly of water and soil. Consequently, nations around the world are investing considerable research effort into developing waste treatment and reduction solutions. Some areas have even enacted bans against the use of the material, however, in the Colombian case, it continues to be highly represented in the industry, and given the low cost of this packaging, little effort has been made to find a replacement. Expanded polystyrene is a thermoplastic polymer with low weight, low thermal conductivity, low cost, and low water absorption; factors which have made it a less attractive target for recycling. It has, however, excellent resistance to mechanical compression, which makes it viable for study in other applications such as those considered in the present study, offering advantages in terms of environmental protection without the need to completely eliminate the use of the material. The present study analyses the effects of integrating waste expanded polystyrene into the process of creating waterproofing paint. The research is divided into three major phases: the first focusing on the determination of the paint’s technical requirements using previous research and by means of initial testing; the second, on elimination tests to validate the properties of various samples before preparing the final paint mixture; and finally, a third phase of final tests required for a waterproof paint. The final formula is applied to common materials in the construction sector, such as wood, metal, glass, and concrete, to validate each of the required properties. Among the main results, technical viability was identified in the second sample, which demonstrated the best results at a ratio of 1: 2.5: 2.5 of waste expanded polystyrene, D-limonene and methyl acetate, respectively.
Determination of the adequate dosage of the soil-cement, using clay of high plasticity
Authors: Rojas-Suárez J P , Orjuela-Abril M S , Prada-Botía G C 
Published: November 2019

Abstract
The clay is used in the area of constructions, ceramics and industrial applications: insecticides, pharmaceutical industry, cosmetics and painting, for its physical and chemical properties that are suitable for different civil projects (roads, public services network, constructions); the dosage is a technique to modify and improve the conditions of the soil-cement in reference to the resistance, conditions of insolubility, impermeability, durability and appearance. In this study, high plasticity clay was evaluated through different laboratory tests (humidity test, soil liquid limit, plasticity index, granulometric analysis, California Bearing Ratio) for three samples and specifying the methodology used in each step, with the objective of knowing its structure and functioning in rural roads in combination with soil-cement, looking for a more profitable and lasting option in this sector, in order to benefit the people surrounding these sectors, improving the income of the sector and seeking to mitigate the environmental impact.
Study of low plasticity clay for optimum dosage of the soil-cement
Authors: Rojas-Suárez J P , Orjuela-Abril M S , Prada-Botía G 
Published: November 2019

Abstract
The need to improve people’s living conditions starts from the reality of the durability of rural road constructions, which have a short useful life and have a negative impact on the inhabitants of these regions. This project aims to improve access to rural areas, rural economic development and thus improve the quality of life of people in the sector; taking into account that at the moment of building a rural road, has a better resistance and durability in time, this was done by analyzing the properties of the clay mixture of low plasticity in the dosage of soil-cement that were tested by tests to determine the liquid limit of soils, determination of the plastic limit, plasticity index, moisture test, classification of soil by sieving, granulometric analysis, unit weight-humidity relations in soils, soil support relationship in the laboratory; in order to find the best dosage that provides greater strength, long-term durability and risk reduction. The results indicate that this type of clay requires an improvement with cement, due to its bearing capacity of 2% and 4%, which gives it a very poor quality to be used in the construction of rural roads.
Comparative for obtaining the optimum dosage of the soil-cement in clays of high and low plasticity
Authors: Rojas Suárez J P , Orjuela Abril M S , Prada Botía G C 
Published: November 2019

Abstract
Dosage is a technique to modify and improve the conditions of the soil-cement that comply with the conditions of the “Instituto Nacional de Vías” standard and in the same way, is economic to be implemented in different types of clay. The clay was classified depending on its plasticity (high plasticity and low plasticity) and the behavior at loads; making laboratory tests of modified proctor, compaction and CBR% for the clays with 4% of soil cement; at the same time, the results of CBR% of soil cement of 4% with natural soils, of 6% of cement and 1 were compared. In this way, was made a proposal of the elaboration of each type of soil-cement with its respective percentage, concluding that the clay of high plasticity can be used for subgrade and the one of low plasticity has a weak bearing capacity.
Rheological, morphological, film and thermal properties of emulsions of polyvinyl acrylic resins, carboxymethyl cellulose and titanium oxide
Authors: Álvarez E , Murillo E A 
Published: November 2019

Abstract
The study of the physical-chemistry properties of dispersions are very importants in the coating industry, since of it depend the application and stability of these systems. Therefore, the aim of this investigation was evaluated the influence of the dispersion rate and titanium dioxide content in the rheological (steady and dynamic analyses), colloidal, morphological, films, and thermal properties of waterborne dispersions based on polyvinyl acrylic resin, carboxymethyl cellulose and titanium oxide. In this work were used two proportions of titanium oxide (5.51 wt% and 10.44 wt%) and the following dispersion rates: 900 rpm, 1200 rpm, 1500 rpm and 1725 rpm. The materials were characterized by rheological, dynamic light scattering, scanning electronic microscopy, adherence, hardness, flexibility and thermogravimetric analyses.
A bibliometric analysis of possible alternatives to achieve the replacement of cellulose acetate in cigarette filters from agricultural residues
Authors: Pachón Colmenares M A , Orjuela Abril M S , Rojas Suárez J P 
Published: November 2019

Abstract
Polymers have become one of the most recognized materials in the industry, due to their good physical properties and the efficiency of their production process, in addition to the versatility and breadth of their fields of application in the aerospace, automotive, construction, textile and adhesive industries. In the case of cellulose acetate, it is used in a wide variety of everyday products such as photographic films, varnishes and cigarette filters, which makes it a factor that negatively affects the environment, since this material takes a long time to decompose and in the process contaminates the place where it is located with particles, on the other side are the agricultural residues that are manipulated in an inappropriate way, generating contamination in landfills and water sources, the following bibliometric analysis was carried out in order to provide a solution to the worrisome situation of this polymer contamination and the agricultural residues contamination, in order to encourage the development of studies focused on producing degradable materials. Therefore, this article presents a bibliometric analysis on the various alternatives to replace cellulose acetate, focusing on the collection methodology and comparison of studies with a tool known as HitsCite. The articles have been investigated by bibliometric, trend and cluster analysis in a sample of 361 articles. The research has been carried out in one of the most recognized databases such as web of science and has allowed to identify the main trends and dynamics of the scientific literature. This in order to mitigate the environmental problems that are present in our environment and being a starting point to support monetary studies that implement environmentally friendly materials, being a topic that can create a positive and innovating impact in the industries commercial sectors.
Characterization of the physical-mechanical and thermal behavior of a clay building unit designed with thermo-insulating attributes and a coffee cisco organic additive
Authors: Narváez-Ortega M S , Sánchez-Molina J , Díaz-Fuentes C X 
Published: November 2019

Abstract
This research is articulated from the clay framework as material wealth of the region of Norte de Santander, Colombia, and seeks to structure attributes of passive thermal cooling in a ceramic piece for low cost masonry type block cooked with physical, mechanical and thermals feasible characteristics for warm tropical weather conditions of 33 °C on average. This work is based on previous studies that explores the partitions structure morphology in Blocks H10 establishing a model of 6 horizontal cavities for low thermal conductivity and having oblique geometry partitions to interrupt heat conduction by direct thermal bridge inside of the constructive unit called Form-C, which is taken as the object of analysis, adding 5% organic coffee cisco additive in the 95% clay mixture to increase the porosity with a proportion that does not affect the deterioration of the mechanical properties and allow to optimize the thermal insulation capacity regarding to a traditional product. Methodologies: in the first phase, prototypes of Block H10 with Form-A are manufactured by extrusion at the laboratory level as a comparative witness of the properties of a standard piece and Form-C as a piece with thermo-insulating strategies to execute physical-ceramic, geometric evaluations of mechanical resistance and water absorption applying the Norma Técnica Colombiana 4017 for masonry units. In the second stage, simulations of temperature distribution and heat flow are prepared by finite element method in ANSYS R16 software to determine the incidence of the variables in the mixture on heat transfer. The results obtained from thermal simulations show an energy decrease of 1.5 °C on average in relation to Form-A. In conclusion, the use of agro industrial scraps and the implementation of passive design techniques in the ceramic piece generate added value in a product that can be industrialized with improvements in technological properties from a thermal efficiency perspective in construction ceramics.
Influence of water/cement ratio on mechanical strength of concrete with partial addition of fly ash and hydrated lime
Authors: Hurtado-Figueroa O , Echavarria-Paez FJ , Cárdenas-Gutiérrez JA 
Published: November 2019

Abstract
Three mixtures were made for conventional concrete with different additions of cement, 300 kg/m3, 350 kg/m3 and 400 kg/m3, being these the 3 designs of mixtures more used for the elaboration of simple concretes. For each of the conventional mixtures, the % of water used for mixing was varied, which constituted 60%, 65% and 70% of the weight of the cementitious material. These % were taken in gradual increase to the one traditionally used in each of the mixing designs made. The aggregates used were assigned by Transmateriales S.A, located in the city of San José de Cúcuta, Colombia. The analysis of the materials of the mixtures, were carried out under the standards of the “Normas Tecnicas Colombianas” and the Tests of the “Instituto Nacional de Vías”. 40% of the concrete mix cementitious material was replaced by fly ash and hydrated lime. In order to determine the mechanical behavior of the mixtures resulting from partial addiction. The ash was collected from the thermoelectric Termotasajero S.A, located in the city of San José de Cúcuta, Colombia. The hydrated lime was recovered from the municipality of Malaga located in the department of Santander, Colombia. Of the % of cementitious material replaced, 30% corresponded to lime and 70% to ash, as an experimental basis for the production of unconventional mixtures. Having the % of cementitious material to replace and the % of substitute material, 3 designs of experimental mixtures were made taking as base each one of the designs of conventional mixtures made, with equal % of water for its mixing. Twenty-seven cylinders were manufactured for the experimental mixtures and the same number for conventional mixtures, a figure that corresponded to the production of 3 specimens per % of water added in each of the established mixture designs. The compressive strength of the cylinders made in the materials resistance laboratory of the Universidad Francisco de Paula Santander, San José de Cúcuta, Colombia was tested. It was concluded in the influence of the % of water in the mechanical resistance of the experimental mixtures and the viability of the use of this type of mixtures in the elaboration of nonstructural concretes, data of importance with which the construction costs would be reduced considerably, generating in turn, a positive environmental impact by means of the inclusion of residual materials in the concrete mixtures.
Evaluation of electrochemical phenomena of fly ash and blast furnace slag in commercial cement mixtures
Authors: Hernández Carrillo C G , Gutiérrez-Junco O J , Sarmiento Rojas J A 
Published: November 2019

AbstractSteel reinforced concrete is the most commonly used composite material in construction; however, large amounts of energy, natural resources are required for its manufacture and is susceptible to corrosion in the presence of aggressive environments. However, there are alternatives aimed at sustainable development, through the gradual replacement of ordinary cement with other Supplementary cementitious materials. Consequently, the present investigation evaluates the effect of fly ash and granulated blast furnace slag on the electrochemical phenomena of steel bars, embedded in a cement paste matrix, characterized by scanning electron microscopy, X-ray fluorescence and area surface to establish variations in electrochemical phenomena evaluated by Tafel extrapolation curves, half-cell potential, resistance to linear polarization and electrochemical impedance spectroscopy. The electrochemical conditions show that the surface areas and composition affect the passivation degree; therefore, mixtures with FA generate passive protection and on the contrary, the mixture with GBFS does not present any type of corrosion protection.