José Aldemar Muñoz

Bio: José Aldemar Muñoz is an academic researcher from Universidad del Tolima. The author has contributed to research in topics: Electric arc & Backpropagation. The author has an hindex of 3, co-authored 5 publications receiving 787 citations.

Edible films and coatings: Structures, active functions and trends in their use

Abstract: Edible films and coatings are thin layers of edible materials applied on food products that play an important role on their conservation, distribution and marketing. Some of their functions are to protect the product from mechanical damage, physical, chemical and microbiological activities. Their use in food applications and especially highly perishable products such as horticultural ones, is based on some particular properties such as cost, availability, functional attributes, mechanical properties (flexibility, tension), optical properties (brightness and opacity), the barrier effect against gases flow, structural resistance to water and microorganisms and sensory acceptability. In this piece of work, the lastest advances on their composition (polymers to be used in the structural matrix), including nanoparticles addition, and properties have been reviewed, as well as the trends in the research about their different applications, including oil consumption reduction in deep-fat fried products, their use in combination with bioactive compounds that bring foodstuff additional functions and shelf life extension of highly perishable products.

Emergency visits for childhood poisoning: a 2-year prospective multicenter survey in Spain.

Abstract: OBJECTIVES:: To describe the characteristics of childhood poisoning leading to consultation to 17 pediatric emergency departments in Spain. METHODS:: During a 2-year period (January 2001 to December 2002), accompanying people of 2157 children with acute intoxication who visited consecutively at the emergency room were prospectively surveyed. RESULTS:: Childhood poisoning accounted for 0.28% of all emergency visits during the study period. The median (interquartile range, 25th-75th percentile) age was 24 months (22-60 months); 67% of children were younger than 4 years. Drug ingestion was involved in 54.7% of cases (paracetamol was the most frequent drug), domestic products in 28.9%, alcohol in 5.9%, carbon monoxide in 4.5%, and illicit drugs in 1.5%. A total of 61.3% of patients were admitted within 1 hour after exposure to the toxic substance, and 10.3% had been already treated before arrival; 29.1% of patients were referred for clinical manifestations which were mostly neurological symptoms. Laboratory tests and other investigations were performed in 40.7% of cases. Gastrointestinal decontamination was used in 51.7% of patients, with activated charcoal in 32.3%. Treatment varied significantly according to the individual hospitals. A total of 83.3% of patients were treated as outpatients, 15.2% were hospitalized, and 1.5% were admitted to the intensive care unit. One 11-month-old boy with carbon monoxide intoxication died. Six patients had permanent sequelae (esophageal stenosis in 5 and partial blindness in 1). CONCLUSIONS:: Young children who accidentally ingested drugs and, less frequently, domestic products accounted for most cases of intoxication who presented at the pediatric emergency department. Language: en

Nonlinear model of a rice drying process using neural networks

Abstract: Background: The production quality of rice is highly depended on the drying process as drying weakens the rice kernel. A look at the production process of rice in the industry was taken. The drying of rice influences the storage capacity of the grain, the energy consumption, the final mass of the grain and the percentage of whole grains at the end of the process. Objective: The main objective was to analyse the drying of rice by making an artificial neural network to model and simulate it. Methods: The modeling of a rice drying process using neural networks was presented. These models are suitable to be used in combination with model-based control strategies in order to improve the drying process. The implementation, preprocessing and data retrieval for the design of an artificial neural system was analyzed. Controlling the drying factors is of major importance. Feedforward and dynamic neural networks were compared based on their performance. Results: It was concluded that when some part of the dataset is given as training, even with one dataset, a back-propagation network simulates very well the other parts of the drying curve. It can be said that the approximations done by the networks to obtain a nonlinear model of the rice drying process are quiet good. Conclusions: Firstly, because of the too little data available for training, the networks were not as good as expected. More data is needed to realy have a powerfull network capable of approximated very well the drying curve. Secondly, a backpropagation network can be a good solution for modelling and for use in a controller if more data is available, in contrast a linear network gave bad results. thirdly, a network with little number of layers is the best option. A perfect mapping from the input to the output is impossible due the differences in each test and the imperfect sensors.

An Alternative Cu-Based Bond Layer for Electric Arc Coating Process

Abstract: A Cu-Al alloy has been used as bond coat between a carbon steel substrate and a final coating deposit obtained by applying the twin wire electric arc spraying coating technique. The presence of a copper-based material in the composite system can change the overall temperature profile during deposition because copper exhibits a thermal conductivity several times higher than that of the normally recommended bond coat materials (such as nickel-aluminum alloys or nickel-chromium alloys). The microstructures of 420 and 304 stainless steels deposited by the electric arc spray process have been investigated, focusing attention on the deposit homogeneity, porosity, lamellar structure, and microhardness. The nature of the local temperature gradient during deposition can strongly influence the formation of the final coating deposit. This study presents a preliminary study, undertaken to investigate the changes in the temperature profile which occur when a Cu-Al alloy is used as bond coat, and the possible consequences of these changes on the microstructure and adhesion of the final coating deposit. The influence of the thickness of the bond layer on the top coating temperature has also been also evaluated.

Edible and Biodegradable Starch Films: A Review

Abstract: Mainly due to environmental aims, petroleum-based plastics are being replaced by natural polymers. In the last decades, starch has been evaluated in its film-forming ability for applications in the food packaging area. Characteristics of the starch film matrices, the film formation methods, and physicochemical properties of the starch films are reviewed in this paper. The influences of different components added in casting methods and thermoplastic processes have been also analyzed. Comparison of mechanical properties of newly prepared starch films and stored films reveals that the recrystallization phenomenon made the films more rigid and less stretchable. These effects can be inhibited by adding other polymers to the starch matrix. Other approaches to improve the starch films’ properties are the reinforcement by adding organic or inorganic fillers to the starch matrix as well as the addition of functional compounds. In this way starch films have improved mechanical and barrier properties and can act as a bioactive packaging. Physicochemical properties of the starch films showed a great variability depending on the compounds added to the matrix and the processing method. Nevertheless, dry methods are more recommendable for film manufacturing because of the greater feasibility of the industrial process. In this sense, a better understanding of the nano and microstructural changes occurring in the matrices and their impact on the film properties is required.