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Chemical thermodynamics is crucial in chemistry because it provides a theoretical basis for understanding the transfer and transformation of energy and matter in chemical processes. Concepts such as energy, work, heat, entropy and enthalpy are essential in molecular biology, engineering and other scientific disciplines. However, the teaching of thermodynamics faces significant challenges due to its abstract nature and mathematical requirements, which diminishes student interest. A perceived disconnect between thermodynamic principles and their practical applications may cause students to consider it irrelevant. In addition, traditional methodologies can negatively affect understanding, while information and communication technologies (ICTs) can make it more attractive. According to surveys, the main problem in teaching thermodynamics is low student interest due to the abstraction of concepts. Teachers can improve understanding by applying innovative methodologies such as ICTs and connecting principles with practical applications. Encouraging critical thinking and problem solving can also improve the understanding and relevance of chemical thermodynamics. [ABSTRACT FROM AUTHOR]

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The fruit seeds, commonly regarded as waste after consuming the fresh pulp, emerge as a source of unconventional starch with innovative potential. This study focuses on highlighting the significance of these seeds by exploring chemical modification methods in this starch source that add value by transforming their properties. The review emphasizes the influence of key factors such as the type of chemical reagent, its concentration, reaction parameters (pH, temperature, time), and the botanical source of the seed on the degree of modification and the resulting morphological and functional properties of the starch. The importance of specific conditioning during the chemical modification process is underscored, as it significantly contributes to enhancing the properties of the modified starch derived from fruit seed. In this regard, new perspectives are opened to efficiently harness fruit seeds, turning them into a valuable source of starch with diverse applications in both the food and non-food industries. [ABSTRACT FROM AUTHOR]

This research aimed to analyze an analogy used in the teaching of stoichiometry in Brazilian textbooks from a structural, semantic, and pragmatic perspective. The analogy being studied compares the fixed proportional relationships between ingredients in a cooking recipe to the relationships between reactants and products in chemical reactions. The analysis involved a review of the chapters in six textbooks that covered the topic of stoichiometry, an identification of the structure of the analogy, its characterization in structural, semantic, and pragmatic terms, and an evaluation of its presentation in the textbooks. The results showed that the analogy, present in three of the analyzed textbooks, has the potential to aid in the teaching of stoichiometry. This is because its structure focuses on the relationships between elements rather than simply describing them, and it is structurally consistent and has similarities in the contextual meanings between the mapped correspondences. The conclusion of the study suggests that although the authors of the analyzed textbooks have not fully explored all of the correspondences identified in the relational structure of the analogy, it offers a wealth of educational opportunities for teaching stoichiometry. This includes teaching concepts such as proportions between reactants and products, equation balancing, excess and limiting reactants, purity, and yield in chemical processes. [ABSTRACT FROM AUTHOR]

Introduction: The balance of materials in obtaining the G-0 intermediate product guarantees that the product is consistently produced and controlled. Objective: Carry out the material balances in the mechanical and thermal operations in obtaining the intermediate product G-0. Materials and Methods: The analysis of the input and output materials mass was conducted for the crude G-0 centrifugation systems, filtration of the suspension to be purified from crude G-0, and centrifugation and drying of the PI G-0. The composition was determined using available techniques and previous research work. For the calculation of the average results of the streams with the Microsoft Office Excel® program 25 batches produced in the years 2016, 2017, 2018 and 2019 were taken into account. Results and Discussion: The material balances per batch in the obtaining of PI G-0 in the systems Centrifugation G-0 Crude, Centrifugation of PI G-0, Filtration and Drying allowed to know the real yield of the desired product for 14 moles of furfural and the losses in the residual streams and due to manufacturing. In the drying operation, the removal of water and wet and dry base solvent was quantified. Conclusions: The material balances in the mechanical and thermal operations of the process of obtaining the intermediate product G-0 allow assuring the consistency of the process. The tests carried out on the specifications: organoleptic characteristics, identification by UV VIS ultraphotometry, melting interval and purity of the product declare the conformity for its use in the production of Furvina. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Investigaciones Agroindustriales is the property of Revista Colombiana de Investigaciones Agroindustriales del Centro Agropecuario Sena Buga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: Steel foundries are significant pollution sites with manual molding and demolding processes, therefore technology has moved on to molding using self-fragrance resins. In this paper, the Life Cycle Analysis (LCA) methodology is applied to evaluate the environmental impacts in a foundry process subject to this technological investment. Objetive: To evaluate the environmental impact of a technological proposal in the molding stage in a steel foundry. Materials and Methods: The input and output flows of the mixtures of sand, gases and solid waste in the traditional molding and chemical molding processes for the production of one ton of steel, as a functional unit, were evaluated and inventoried. SimaPro 8.0 software was used to obtain LCA results. Results and discussion: The results demonstrate the economic and environmental feasibility of chemical molding. In the analysis, it was verified that the return sand is the raw material with the greatest benefit to the impact categories, favoring from climate change to human health and limiting the formation of particles that affect health, ecosystems and natural resources. Conclusions: The LCA methodology quantifies the environmental impacts of steel production and justifies the economic-environmental feasibility of chemical molding, verifying that the return sand is the raw material with the greatest contribution to the impact categories and, as an avoided product that is recycled, favors in the new technology the environmental and damage categories. [ABSTRACT FROM AUTHOR]

Copyright of Roca: Revista Científico-Educacional de la Provincia de Granma is the property of Universidad de Granma, Departamento Editorial and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Species identification from timber helps combat ilegal wood trafficking. In the present work, it is shown a method that aims to detect wood species from previously cut and stored pieces through the interaction of the volatile compounds that they emanate with an array of chemical sensors (electronic nose). The device processes the response of the chemical sensor array using linear regularization and probabilistic machine learning methods trying to resemble current biometric systems. In particular, this method includes a heuristic parameter estimation stage on the signals provided by the sensor array, followed by a variable selection stage through L¹ regularization, to finally use Gaussian mixture models [GMMs] for the process of probabilistic modeling. As a result, a performance (measured by EER) of 17.5 % is obtained for the detection of four wood species; and, for the particular case of Sapán, an EER of 12 % is achieved. In conclusion, this biometric approach gives good results compared to previous works, taking into account that in the present work, the experiments are carried out in conditions that are closer to reality. [ABSTRACT FROM AUTHOR]

Glyphosate is a widely used herbicide, however, its detection in water is an environmental problem due to its character as an emerging pollutant. The advanced oxidation processes - AOP are used for its degradation on materials modified with iron. In this study, the adsorption and catalytic degradation capacity of glyphosate was evaluated using bentonite and kaolinite impregnated with iron. The impregnated materials were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy (SEM), to determine structural changes, monitoring of incorporated iron content, and morphological changes, respectively. Subsequently, adsorption tests were carried out using aqueous glyphosate solutions in a concentration range between 12-27 mg/L of glyphosate, using UV-Vis spectroscopy for their quantification, the results showed that both bentonites and kaolinites impregnated with iron reached up to 55 % adsorption of the herbicide. Analysis by FT-IR showed that the impregnated bentonites after the adsorption process exhibit chemical interactions with the herbicide. The catalytic tests revealed that the materials used in this work and under the tested measurement conditions present a degradation percentage of up to 34%. [ABSTRACT FROM AUTHOR]

Contextualization: Solid ruminal activators (SRA) that improve fermentation conditions in the rumen microorganisms of the cattle, used as feed additives, have gained importance in the nurturing of ruminants. They promote animal production rates and replace growth promoters, such as antibiotics, that can affect animal production and influence on their consumers microbiota; consequently, they can strongly affect human health. Knowledge gap: The solid ruminal activators are important mitigators of the generation of greenhouse gasses because they improve the digestibility of fibrous and coarse foods, widely used in the feeding of ruminant species, which are important generators of greenhouse gasses. Purpose: In the present study, three SRA were inoculated, in different percentages (0, 10 and 15%), with a microbial preparation composed of lactic acid bacteria (LAB). They were evaluated to assess the composition and microbiological quality of these food supplements. Methodology: Multiple samplings were carried out throughout the manufacturing process and several chemical and microbiological analyzes of the samples were performed. Results and conclusions: Supplements with crude protein (CP) values higher than 22%, low crude fiber content (CF) and in vitro dry matter digestibility (DVDM) higher than 80% were found in all cases. In addition, it was observed that SRA are innocuous from a microbiological point, which makes them a possible probiotic due to their high loads of LAB. In this sense, SRA are an efficient, biotechnological, alternative that could be used in cattle feeding to improve the use of forage and fibrous materials; also, they contribute to improve the environmental conditions because they support the decrease of greenhouse gasses. [ABSTRACT FROM AUTHOR]

The problems that affect the efficiency of the quality of the management of the soap production process in a chemical production company are determined through the development of a procedure. Tools such as document analysis, interviews, graphic analysis, Pareto diagram, Brainstorming, Cause-Effect diagram, OTIDA diagram, descriptive statistics, and quality costs are used. Theoretical methods were used: induction-deduction, historical-logical, analysis and synthesis, and hypothetical-deductive. The evaluation of management efficiency based on this procedure is 1, on a scale of 1 to 5, and a qualitative evaluation of Very bad. 76.8% of the failure costs are costs due to loss of time in the production process by towing the raw material. [ABSTRACT FROM AUTHOR]

The present study analyzes the assessment of vanadium concentrate as an alloy charge for coated tubular electrodes intended for recharging parts. The concentrate was obtained from the chemical processing of flat catalysts from sulfuric acid production, mixed with charcoal. The 3.5 mm diameter electrode was made with a 10 x 1 mm AISI 1010 steel strip and coating with 70% calcite, 10% fluorite and 20% graphite, which guaranteed good technological performance. Weld beads with 0.19% C were obtained; 0.19% of V; 1.94% Cr and 0.1% Mo, with the presence of fine-grained ferrite in the columnar and acicular zone in the center of the bead and 208 and 187 Hv hardnesses respectively. [ABSTRACT FROM AUTHOR]

Copyright of Index: Revista de Arte Contemporaneo is the property of Pontificia Universidad Catolica del Ecuador and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ingeniería del Agua is the property of Universidad Politecnica de Valencia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Adsorption minimizes the generation of toxic waste and the recovery of metal. The objective of the work was to study the bioadsorption of chromium (VI) and lead (II) using dry biomass of the strain Kluyveromyces marxianus CCEBI 2011. It was worked at different pH values and concentration levels. The determination of the chemical-physical parameters was carried out at the Geominera Oriente Company. Adsorption isotherms were carried out by the Langmuir, Freundlich and Dubinin-Radushkevich models, resulting in that the maximum bioadsorption capacity of chromium (VI) and lead (II) by biomass was 0,89 and 4,61 mg g-1, respectively. the removal percentages being greater than 90%. The mean adsorption free energy values obtained from the Dubinin-Radushkevich model in chromium (VI) and lead (II) were 10 000 and 15 811,4 kJ mol-1, respectively, showing that for these experimental conditions the adsorption process is of chemical nature. [ABSTRACT FROM AUTHOR]

Copyright of Ingeniería (0121-750X) is the property of Ingenieria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista ION is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: The article addresses to problem of evaluate productions growth possibilities in chemical industry. A heuristic procedure is proposed that includes possibilities of a new investment or modernizing and intensifying an existing installation evaluation. Specifically, the possible solution for sulfuric acid production is analyzed, in which the existence of an industrial facility in Matanzas province, Cuba, founded in the 1940s plays a key role. Objective: To apply an elaborated strategy to increase the availability of a chemical product with minimal investment expenses on scientifically founded bases. Materials and Methods: A methodology is proposed that is applicable to the country problem solution. The methodology consists of several stages that allow: problem determination, problem magnitude measurement, chemical products mesh definition, technological study, plants to satisfy needs of these products' existence or not, as well as the need to modify them or to make new investments and to carry out the investment technical economic study. Results and Discussion: The studied process of Matanzas' sulfuric acid plant is a typical case in which an installation modernization is required. The proposed methodology is applicable to evaluate alternatives for chemical industry development. Conclusions: The proposed methodology is applicable to evaluate alternatives for chemical industry development. The studied process in Matanzas' sulfuric acid plant is a typical case in which an installation modernization is required. [ABSTRACT FROM AUTHOR]

Copyright of Inventum. Ingenieria, Tecnologia e Investigacion is the property of Corporacion Universitaria Minuto de Dios and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The allophane is a natural nanoparticle present in soils from volcanic origin such as andisols, which are distributed worldwide, especially in countries that have active volcanoes. In Ecuador, andisols are in high and humid areas from the Highland/North region, constituting 30% of the territory. The allophane can be obtained from andisols through physical and chemical processes or it can be also synthesized. This nanomaterial has multiple properties for various applications in different areas; and there are studies about these nanoparticles and this kind of soil, but they have not yet been conducted in Ecuador. This article presents a review of structural characteristics, properties, formation, isolation, synthesis and uses of allophane to extend knowledge and encourage the conduction of research in these soils, which are the source of the aforementioned nanoparticle. The literature review was performed on Science Direct and Google Scholar databases using high impact articles related to natural or synthetic allophane. Allophane has characteristics that allow it to be used as an environmental remediator, bactericidal, anti-inflammatory, flame retardant, enzyme support and also in catalysis, photocatalysis and electrocatalysis. Considering the availability and the large area covered by andisols in Ecuador, research based on international investigations can be perform to take advantage of it. [ABSTRACT FROM AUTHOR]

Introduction: agricultural waste is increasing worldwide. It is necessary to identify new strategies for its valorization. Objective: analyze the main processes of transformation of biomass to be implemented in the use of the waste of the plantain agroindustry. Methodology: the information was consulted in different databases such as Web of Science, Scopus and Google Scholar. Different keywords in English and Spanish were used: waste; process; transformation; banana and plantain. The information was analyzed in MS Excel. Results: the physical and biological conversion processes can be an alternative for the waste valorization of plantain agroindustry in different value-added products such as animal feed and biofuels due to the quantity and composition of this type of waste. The high moisture content of this waste is an inconvenience to its valorization. It is necessary to extract an amount of water from the matrix to increase the efficiency in the transformation. Conclusions: the design and techno-economic, environmental and social assessment of physical and biological conversion processes in the context on biorefineries can support investment and research decisions in this type of technologies to be implemented at a large scale. [ABSTRACT FROM AUTHOR]

This document presents a brief history of catalysis, as well as of the selective oxidation processes of hydrocarbons. On the other hand, the basic concepts involved in heterogeneous catalysis are addressed, emphasizing the role of catalytic materials in chemical oxidation processes and posing a series of guiding questions that must be followed when addressing a process catalyzed by solid materials. In the same way, the preparation methods known in the literature as sol-gel and impregnation are shown, identifying the influence of each preparation step with the physical and chemical properties of the materials. Finally, a case study applied to the selective catalytic oxidation of methane and methanol using iron, molybdenum, and vanadium catalytic materials synthesized by the sol-gel method is presented. [ABSTRACT FROM AUTHOR]

The set of quantitative methods and techniques used to detect assignable variations in manufacturing processes are contained within a discipline classified as statistical process control. Such methods carry out precise evaluations on the general state of productive systems and carry out simultaneous monitoring of various interrelated quality characteristics. In the framework of this research, the analysis of a chemical process based on the theoretical principles of principal component analysis is proposed, which enables the representation of the original variables in a compact dimensional space. In the later phase, a control graph based on the squares of the prediction errors is constructed in order to evaluate the behavior of the composite variables found. The results indicate that the process is not marginally stable and it is necessary to reduce its variability margin. [ABSTRACT FROM AUTHOR]

Introduction: Food process design has often been approached using methodologies developed for chemical process design. These particularities demand that the design engineer explore other alternatives focused on guaranteeing product quality. In Ecuadorian Amazon context, cane derivatives process is carried out in small artisanal units designed with insufficient technical criteria. This affects final product quality and producers economy. Objective: To propose a procedure that, from the conceptual design, considers product quality. Materials and methods: A procedure was used that considers product quality from the conceptual design, which consists of eleven activities and three decision-making. It is supported by GNU Octave software for process simulation and optimization using the objective function (FO) that maximizes the net present value (NPV) and as a novel aspect, the FO minimizes quality indicators variance. Results and Discussion: In the applied study case, the operational range was determined as: a pH of 3.63 to 4.16, °Brix from 75.12 to 76.73 and NPV fluctuates between 2 603 469.38 USD to 6 669 971.27 USD with a sigma level greater than three. Conclusions: Uncertainty of operational variables decrease increases product acceptability and this is reflected in optimal values obtained from the NPV and quality attributes. [ABSTRACT FROM AUTHOR]

The main objective of this research study is to model the equilibria in the separation of butanol using the extractant 2-ethyl-1-hexanol (2E1H). Binary parameters were fitted using MATLAB's default genetic algorithm function and a solver for nonlinear curve-fitting ('lsqcurvefit'). The products assessed in the ternary equilibria were ethanol, butanol, acetone, and acetic acid and were simulated using UNIQUAC. The root mean square deviation (RMSD) of the prediction for these ternary liquid-liquid equilibria was 1.4, which is 4.7 times lower than that achieved by using Aspen Plus V10® parameters, a top commercial software for simulating industrial chemical processes. It is recommended to use the maximum possible amount of experimental data of liquid-liquid equilibria to achieve simulations with the lowest error possible. It is not recommended to use Aspen Plus V10® parameters for butanol extractions using 2E1H. [ABSTRACT FROM AUTHOR]

The chemical process simulators represent a competitive and functional tool that effectively supports the study of processes as complex as the thermochemical conversion of biomass, specifically in the modeling and simulation of the same. The programming modules of a simulator for systems in liquid- vapor equilibrium with excess thermodynamic properties, applied in forest biomass conversion processes such as pine saw (Pinus Arizonica), are designed and validated. The design involves the calculation of the equilibrium constant by the fi-gamma method with new computational tools for the prediction of the properties of the phases in equilibrium and the calculation of the activity coefficient based on the mathematical models of local composition NRTL, UNIQUAC, and UNIFAC. The Newton-Raphson method was chosen to solve computation subroutines. In the validation twelve (12) new components were incorporated into the library and sub-modules of the properties of the liquid and vapor phases. The estimation of the bubble and dew points for all methods yielded mean errors of less than 3%, and the composition of the vapor phase and the properties of the equilibrium phases did not exceed 10%. [ABSTRACT FROM AUTHOR]

Copyright of Revista Fuentes, El Reventón Energético is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present investigation is focused in defining the quality of the concrete in built existent constructions with the system precast concrete Great Soviet Panel. They are necessary the speed of the ultrasonic pulse, surface methods and other parameters like the humidity and the potential of corrosion. When analyzing the results, you conclude that, in the elements precast concrete in good technician-constructive state that they conform the constructions in exploitation, the quality of the concrete is half. However, in the elements with presence of pathological damages the quality is poor. In these damaged elements, processes of chemical deterioration are evidenced, caused by the attack of the water that they generate formation of compound soluble of the pasta, the loss of mass, of mechanical resistance among other alterations. Equally the carbonation of the concrete is unchained that causes the corrosion of the reinforcement steel in turn. The realization of destructive rehearsals is recommended to obtain the resistance to compression of the elements, it stops this way to value the incidence of the durability of the concrete, in the behavior structural seismic of the built constructions with this system precast concrete. [ABSTRACT FROM AUTHOR]

This article studies the environmental factors produced by the textile sector (dyeing, finishing, printing and denim washing) in the Valle de Aburrá. This industry consumes chemicals within its processes and, consequently, causes environmental pollution, which has prompted the implementation of legal regulations that establish controls and monitoring. Hence, this sector must identify the environmental factors affecting its processes in order to develop strategies to minimize the pollution produced. Using a qualitative methodology with a descriptive approach, the control variables are described, according to their productive activity, which are related to water and chemical consumption in their processes, establishing the environmental factors. An interview was conducted with 34 companies in the sector. It was possible to identify their distribution in the AburráValley and the strategies they are developing based on environmental factors. In this way, it was established that the companies are carrying out the management of ecological products, the improving of the processes for the recovery of resources and the management of the environmental legal matrix to comply with the levels of control and monitoring expressed in the legal regulations. [ABSTRACT FROM AUTHOR]

A study aimed at promoting the saccharification of brewer's spent grain through the application of commercial enzymatic complexes is presented. Brewer's spent grain corresponds to a potential lignocellulosic residue for its introduction in biorefinery processes given its chemical composition and high volume of residual material. In this context, Viscozyme L, Celluclast 1.5L, Hemicellulase and Xylanase were evaluated according to the dosage in order to maximize the response in reducing sugars. Enzymatic hydrolysis presented a significant effect, obtaining the best results for the Viscozyme L complex with a maximum glucose release of 16.9 g/L. The results indicate that the implementation of the Viscozyme L complex is possible, allowing cleaner and energy efficient processes. [ABSTRACT FROM AUTHOR]

Introduction- The non-energy use of high-range carbons (anthracite) has great potential in industries such as metallurgy and in the synthesis of new carbonaceous materials. However, before being used in these applications, they must be treated to remove impurities or unwanted compounds. Objective- To evaluate the efficiency of the process of chemical demineralization of semianthracites through the use of different acids varying the operating conditions of the process. Method- Two samples were chemically characterized: Boavita (B) and Capitanejo (C) from the Boyacá and Santander (Colombia) mines, respectively. Ash and mineral matter removal from the samples was evaluated using [HCl] = 5M, HF 40% and HCl 38% at two different reaction times (45 and 60 minutes) and two particle sizes of the material (250 and 500 µm). Results- The minimum values of ash content (bs) reached through the demineralization process for samples B and C, were 0.65 and 0.76% respectively, which were obtained with a particle size of 250 µm and 60 minutes of exposure in each of the acids used in this study. Conclusions- A smaller particle size increases the contact surface and improves the degree of demineralization, regardless of the time of exposure to acids. The efficiency of the chemical benefit shows yields in the reduction of silicates, aluminates and aluminosilicates to 100%, while for ferric minerals it is above 50%. [ABSTRACT FROM AUTHOR]

Introduction- Soils found in tropical zones, as they are subject to factors that favour the chemical meteorisation process, tend to have particular geotechnical properties as opposed to those found in temperate zones. Fundamental aspects such as the degree of meteorization and genesis of the material, which tend to influence soil properties, are not taken into account by the methodologies intended to study the characteristics of these soils. Consequently, they are insufficient, requiring complementary procedures for an adequate description of the geotechnical characteristics of the material. Objective- To propose a methodology for the characterization of a tropical soil derived from volcanic rocks. This is an attempt to adequately describe this type of soil and extrapolate it to soils of tropical regions derived from different rocks. For this purpose, a tropical soil located on a slope southwest of the municipality of Caldas in Antioquia (Colombia) was taken as a case study. Methodology- An experimental program was developed to evaluate the physical, chemical, mineralogical and hydro-mechanical properties of the material in the study area. Results- It was found that the relationship between the degree of weathering and the genesis of the material have an influence on the geotechnical properties evaluated. Conclusions- With this methodological proposal it was possible to evaluate important aspects such as the degree of meteorization and genesis of the material, obtaining not only basic geotechnical parameters for the analysis, design and execution of civil projects but also a better description of the material. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Sociedad Química del Perú is the property of Sociedad Quimica del Peru and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Trophic state indices are important tools used in ecology to establish trophic classifications as they are robust and provide appropriate information to implement coastal zone management criteria. In order to diagnose the trophic status of a hypersaline tropical coastal lagoon called Las Marites, located in southern Margarita island, Venezuela, the Karidys and TRIX indices were applied, combined with comparisons with reference values. Historical data of concentration of nitrate, nitrite, ammonium, phosphate, chlorophyll and dissolved oxygen in surface water level were used. The results showed that Las Marites lagoon has nutritional characteristics of eutrophic environments. However, this does not imply that there is a process of eutrophication, at least at intermediate or advanced stages, since the main symptoms of this process, water coloration due to massive algal growth, were not observed. Probably, this is due to the particular hydrodynamic and morphological conditions of this lagoon, which allow rapid renewal of the water and the complex chemical processes that occur within hypersaline lagoons. Only slight alterations were observed in the western sector. There were no seasonal changes, so that precipitation does not alter the trophic conditions of the lagoon. Temporarily, a tendency to deterioration of the trophic state was observed. [ABSTRACT FROM AUTHOR]

The current industry requires of the fault diagnostic systems with a detection stage that can ensure a small number of false alarms and a quick detection of faults, regardless of their nature and magnitude. However, a common problem of the approaches based on the Multivariate Statistical Process Monitoring (MSPM) which are currently used for this purpose is the difficulty of them to detect small magnitude faults without incurring a high number of false alarms, and faults not detected. To overcome this drawback, in this paper is proposed a novel approach that combines the advantages of kernel methods, and a novel EWMA with enhanced dynamic to filter the T² Hotelling statistic used as the fault detection mechanism in a complex chemical process. [ABSTRACT FROM AUTHOR]

In Cuba, powder detergent production is carried out by a single factory. This work research was intended to evaluate the powder detergent production process from a simulation process. For this purpose, the HYSYS v. 3.2 chemical process simulator was employed and definition of properties of hypothetical components that are nor part of the pure components database was required. Results of the basic case showed inefficiencies of the process operation, the most important being during the neutralization stage and the drying gas heating stage. Results of Study Case 2 show that it is possible to reduce pH of the neutral paste to 15.34% when compared to the basic case, for a production of 848 kg neutral paste per hour, without affecting the percentage of the active ingredient. Additionally, a decreased consumption of liquefied gas of 1,500 L/d implies increased profit in the amount of $ 227,301 per year, compared to the basic case. [ABSTRACT FROM AUTHOR]

In this work, the main quantitative techniques for technological risk assessment in industrial chemical processes are studied, classified and categorized. It is specified that these techniques are the most useful to evaluate, in a comparative way, the design alternatives, operations and maintenance. It is specified that these techniques are able to assign occurrence values to the identified different risks, that is to say, to calculate the level of risk of the different stages of the project. In addition, it enumerates all those techniques that present a bigger use frequency as well as the dangers they identify and the results they give. In function of the grade of complexity of the analysis technique, their use is linked with the different stages of the life of the industrial projects/processes. [ABSTRACT FROM AUTHOR]

Objective. Obtain clarified cashew juice, in order to sensorially evaluate clarified and optimized juice and establish chemical differences between the integral and the clarified juice. Materials and methods. The pseudo fruits were manually separated from the nut and were selected and washed, then scalded and the juice was extracted. The natural juice and the most accepted one were chemically characterized. Juices submitted to sensory evaluation (acceptance) with a 9-point hedonic scale and a test system for 30 tasters. A three-level factorial design combined with response surface methodology was used. The chemical characteristics of juices were analyzed by Levene's test for homogeneity of variances and T-Student test for comparison of means for independent samples. Results. The evaluated juices displayed no statistically significant differences (p ≤ 0.05, p ≤ 0.01), but the highest percentage of acceptance was for the juice treated with 0.20% w/v Rapidase® CX and 14.27 hours at 30°C, differences were statistically significant for pH, °Brix, reducing sugars and ascorbic acid (p ≤ 0.05), furthermore, the content of ascorbic acid was significantly reduced by 41.01% compared to the initial juice. Conclusions. The clarified juice with high vitamin C content, obtained by enzymatic treatment, is a way of agro-industrial use of the pseudo fruit, having been accepted for consumption, and non-astringent, with good flavor, aroma, by treatment with 0.20% w/v Rapidase® CX and 14.27 hours at 30°C. [ABSTRACT FROM AUTHOR]

This paper presents a study on the chemical, thermal and structural properties of chachafruto's flours and starches. A proximal analysis was performed both flour and starch of chachafruto (Erytrina Edulis Triana Ex Micheli) determining parameters such as moisture, minerals, protein, fat, fiber and starch percentage. The thermal properties were determined with the techniques of differential scanning calorimetry, thermogravimetric analysis and Rapid Viscoamilography Analysis and structural were determined by X-ray diffraction and scanning electronic microscopy. The proximal analysis for flour presented: moisture 12.33%, ash 1.55%, 18.5% protein, ether extract 2.50%. For starch: Moisture 12.60%, 0.90% ash, ether extract 1.82% and 0.8% protein. Starch granules spherical and ovoid forms submitted. The TGA for flour showed a temperature of moisture loss of 119.99°C, the maximum temperature of decomposition was presented in the 272.5°C and finally the process ends at 581 °C. Starch granules presented spherical and ovoid forms. To the flour, the temperature of moisture loss was 119.99°C, the maximum temperature of decomposition was presented in the 272.5°C and finally the process ends at 581 °C. For starch, the decomposition of water was established at 200.94°C, the maximum temperature of decomposition showed a peak at 300°C and the process ended at 584.72°C. When performing the DSC analysis for the flour was found that the characteristic temperatures for the gelatinization process are TO= 62.06°C, TP= 70, 98°C, TF=78.62°C and for starch was obtained that TO= 56.65°C, TP= 70.06%, TF= 85.1 2°C. [ABSTRACT FROM AUTHOR]

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the present work local and global descriptors of the reactivity were calculated for sunset yellow and allura red to analyze its intrinsic reactivity. The computational calculations were carried out in vacuum and aqueous phase. The aqueous phase is represented by a dielectric constant of 78.5, introduced by polarizable continuum model. The results show that allura red is less susceptible to nucleophilic addition than sunset yellow, because the electrodonor substituents methyl and methoxy decrease the capability of the azo group to accept electrons. The analysis of condensed Fukui function for a nucleophilic attack and local electrophilicity index showed that the preferred direction of attack the reducing agent (bisulfite ion) occurs on C4, which was in good agreement with experimental reports. [ABSTRACT FROM AUTHOR]

Copyright of Revista ION is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present work presents a novel theoretical model that allows visualizing the chemical reactions evolution in a specific multicomponent reactive distillation process. Math provides tools to represent real processes for analysis, and with the basic elements of linear algebra chemical species and chemical reactions could be represented by linear combinations of natural elements and homogeneous equations systems, respectively. A subset of an L-dimensional space is required for the graphical representation of these mathematical objects. A reactive diagram is drawn as a study case. This diagram allows locating the involved chemical species as well as their temporary evolution through a batch reactive distillation process. Furthermore, in this triangular diagram, the behavior of that system can be visualized. [ABSTRACT FROM AUTHOR]

In this work a method for the scaling of chemical and biochemical processes based on a phenomenological model is presented. Concepts such as operating point and operating regime of a process are defined to propose a tool based on control theory to process scaling, the Hankel matrix. This methodology was applied to a fermenter for producing ethanol from glucose syrup. The values of the design parameters gave errors below 10% when they are compared with values reported in the literature, for both laboratory scaling and for an industrial scale. [ABSTRACT FROM AUTHOR]

Accelerated tests together with electrochemical impedance spectroscopy (EIS) analysis, are powerful tools to follow up the degradation process of organic coatings under controlled conditions in relatively short periods of time. This work presents a review of the most common accelerated methods, coupled with EIS measurements and applied to organic coatings on galvanized steel under simulated atmospheric environments. [ABSTRACT FROM AUTHOR]