Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The determination of cryoscopic temperature is an important parameter in the calculation of low-temperature processing modes of frozen products. The process of rapid freezing is accompanied by temperature changes, therefore, to develop energy-saving and effective methods of preserving and processing fruit and berries, it is necessary to accurately determine some variables that affect the result of freezing. The study aimed to develop a differentiated analysis technique for determining the cryoscopic temperature and the crystallization temperature of the eutectic points of sucrose and glucose solutions. To determine the cryoscopic temperatures in the study, the method of thermal analysis based on the construction of freezing thermograms was used. The study was conducted using berries grown in the Kemerovo region (Russia). As a result of the study, it was found that the cryoscopic temperatures were most influenced by the total (free and bound) moisture content and organic and mineral substances in berry juices. The authors also determined cryoscopic temperatures of different black currant, sea buckthorn, and juneberry varieties. The developed technique will allow for the simulation of freezing processes under various processing conditions.

Shell and tube heat exchangers are the most common type of heat exchangers, and are applicable for a wide range of operating temperatures and pressures. In the present work the thermo-hydraulic rating of a shell and tube heat exchanger was carried out, in order to perform the condensation of a methanol stream using water as coolant. The overall heat transfer coefficient for both the sensible-heat and latent-heat zone had values of 166.41 W/m2.K and 1,198.39 W/m2.K, respectively; while the required total heat transfer area and percent excess area had values of 38.08 m2 and 3.05 %, respectively. The pressure drops of methanol and water streams reached the values of 51,490.84 Pa and 2,890.50 Pa, respectively. The proposed shell and tube heat exchanger can be employed satisfactorily for the demanded heat transfer service, since the calculated percent excess area does not exceed 25%, and the pressure drop of the water stream does not exceed the value of 80,000 Pa.

In Nicaragua, studies of the western Malacofauna are relatively few, mainly for the Gastropoda subclass, having as the only references within the country studies carried out by MARENA, COMAP, USAID and FUNCOD in 2002, in which they identified about 106 species among flora and fauna, in which some bivalves are mentioned, on the other hand Santana Aguilar in 2006, identified 70 species of bivalves and 92 gastropods in the Cosigüina Natural Reserve, last but not least the books compiled by López and Urcuyo in 2008 , who make a record of the main characteristics of both subclasses, dividing the information into two volumes, one for each one, giving a photographic record at the end of each taking of the most common bivalve and gastropod species in the Pacific. However, these studies do not take a specific record of the coastal part of León, which presents a diversity of species of both subclasses and that are of great commercial interest for the community, since it is their source of economic income, therefore, The initiative arises to carry out this study on Santa Lucia Island, which is considered a buffer zone of the Juan Venado Nature Reserve, sharing species of both flora and fauna. The study was carried out in the months of September to November, after the end of the closed period of the Bivalvia subclass, taking samplings every 20 days, taking as a reference the northeast coastline of Santa Lucia Island, the coves of "El Rosario" and “El Gancho” (which are characterized by presenting the largest bivalve station and some gastropods, according to locals), a total of 360 specimens were captured, of which the presence of 19 species was identified in sizes from 1 centimeter to 22.9 centimeters, predominating in the case of the bivalves the genus Anadara sp., Of the subclass of the gastropods, the species of Rhinocoryne homboltdti, followed by Cerithidae sp., And Ilichione subrugosa, with the coastal zone presenting the greatest diversity of species of the gastropod subclass In comparison to the coves, however, the coves presented a greater dominance of species of the Bivalvia subclass.

Trichodermas mushrooms are of vital importance to keep plant crops free of phytopathogenic fungi, so the present research consisted of finding the best organic substrate for the mass reproduction of Trichodermas fungi, previously identified from Nicaraguan soils. Substrates were used such as Rice in the control, Corn, Corn cob, Coconut Copra and Molasses as a supplement to the before mentioned substrates, with 5 strains, previously identified as Trichoderma harzianum (72TG-11), Trichoderma harzianum (T3), Trichoderma harzianum (CVD-06), Trichoderma sp. (CIXD-11) y Trichoderma longibrachiatum (QIVD-12). Through solid and biphasic fermentation, the spore production process was carried out for 26 and 15 days, respectively; obtaining as a result that the corn cob substrate yielded spore concentration very close to those obtained with the rice substrate. With molasses addition to the different substrates, a slight increase of the concentration spores compared to those obtained in substrates without molasses was obtained, except with the strains T3 and CVD-06, where apparently there aren´t appreciable difference in the number of spores obtained. In the other hand, corn cob substrate is the best substrate for mass reproduction of Trichodermas fungi, since satisfactory results are obtained in both fermentations and there aren´t competition with human being food.

The authors conducted this study to assess the influence of the strength properties of packaging materials for baked confectionery products on the tensile strength, fracture strength, and elongation level. The purpose of this study was to evaluate the mechanical properties (impact strength, fracture strength, and distance to fracture). The paper presents a brief overview of modern methods of functional and operational properties control for polymer packaging materials used for food products and describes their features. The objects of the study were samples of packaging for gingerbread purchased from trade organizations. It has been shown that quality control of polymer packaging materials for food is key in determining the possibility of their intended use. The test results allow evaluating the possibilities and limitations, optimizing the technological process, and obtaining high-quality packaging. In conclusion, the authors give recommendations to gingerbread manufacturers to increase the competitiveness of the product and meet consumer demand.

The slaughtered animals’ blood is a valuable secondary raw material in the meat industry. In this investigation, we propose a separation freezing technology for the blood, blood plasma and hemoglobin solution concentration. The processes of secondary meat raw materials separation freezing were studied for which the experiments for freezing in a capacitive crystallizer were conducted. The dependence of the freezing duration on the heat exchange surface temperature is determined and the cryoconcentration efficiency criterion is calculated. It is proved that the greatest freezing efficiency is observed at the heat exchange surface temperature of minus 2°C. At this temperature, the lowest dry matter loss was observed. The experiment in the separation freeze drying of a hemoglobin solution with the use of re-cryoconcentration was conducted. It is established that this technology can significantly reduce the dry matter loss. The pig blood plasma analysis before and after crystallization was conducted. It was found that crystallization has almost no effect on the amount and ratio of amino acids in the product.

In the modern world, sports facilities are multifunctional complexes that not only meet the needs of the sports infrastructure but also serve as recreational facilities. Sports buildings and facilities are constructed using large-span structures and require significant urban areas for their erection. The paper discusses the results of research carried out by the Moscow State University of Civil Engineering, which provides for the efficient use of the building area of sports facilities and the reduction of the cost of facilities through the use of space within the large-span structures for the placement of a large number of sports infrastructure facilities. The key issue in solving the problem of compactness of the developed area is the use of large-span structures of intermediate floors. Based on the selected cases, the authors classify approaches in the design of sports buildings, based on the use of three types of large-span floor structures: steel-reinforced concrete floor slab, load-bearing floor, and building-bridge. The authors conclude that these approaches can be used in the design of various types of sports facilities: from the municipal level of sports and recreation complexes to facilities designed for major international competitions.

Shell and tube heat exchangers are the most common type of heat exchangers, and are applicable for a wide range of operating temperatures and pressures. In the present work the thermo-hydraulic rating of a shell and tube heat exchanger was carried out, in order to perform the condensation of a methanol stream using water as coolant. The overall heat transfer coefficient for both the sensible-heat and latent-heat zone had values of 166.41 W/m2.K and 1,198.39 W/m2.K, respectively; while the required total heat transfer area and percent excess area had values of 38.08 m2 and 3.05 %, respectively. The pressure drops of methanol and water streams reached the values of 51,490.84 Pa and 2,890.50 Pa, respectively. The proposed shell and tube heat exchanger can be employed satisfactorily for the demanded heat transfer service, since the calculated percent excess area does not exceed 25%, and the pressure drop of the water stream does not exceed the value of 80,000 Pa.

Micro, small and medium enterprises are a very important part of any economy in the world. In Mexico they represent more than 90 percent of the existing companies. A challenge facing these organizations is the acquisition of knowledge and the ability to absorb it. These companies can bring knowledge from abroad to take advantage of it and use it within their internal processes, but how do they acquire knowledge and how do they take advantage of it for the functioning of their organizations? Within this research, a case study was carried out in three companies, where routines and activities were identified within the four dimensions of knowledge absorption capacity: Acquisition, assimilation, transformation and exploitation. As a result, the knowledge absorption process of organizations was obtained, that is, a set of routines and activities that these companies carry out to absorb knowledge.

In social networks, depending on the settings established in the user profile, anyone can see personal information; this includes very personal data, such as who the relatives are, their place of work, and the school they attend, among others. The more information shared, the greater the risk of compromising the profile on a Social Network, which could cause being exposed to extortion, harassment, violation of privacy, usurpation of profile or identity, among other dangers due to the inappropriate use of social networks on the Internet. In this work, a program was developed, with which, through the Application Programming Interface (API) of a social network such as Twitter, it will be possible to know from which device or application the publication was made, until knowing the place and the date that publication was made.