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[en] This research is developed within the framework of the environmental conditioning of houses in warm-humid climate and the obtaining of optimal thermal comfort conditions by passive means. The study of the thermal insulation of the dwelling is considered as an influencing factor in the achievement of the best habitability levels. The study focuses on a representative typology of dwelling in Havana (Cuba). Its geographical location makes this city one of the reference locations for the warm-humid climate. [1, 2, 3]. The effects and the influence of the additional insulation to the enclosure are analysed here. In order to achieve the targets proposed, the hourly evolution of the indoor air temperature under different environmental situations has been analysed using the dynamic simulation software: Transient Energy System Simulation Tool (TRNSYS 16.1). This is a modular and flexible software, that allows complex systems to be designed and the input variables and the contour conditions to be modified at each step time. Early results give a slight hint of the thermal behaviour of the dwelling under perimeter insulation conditions. In fact, these results justify a priori the quite widespread perception in the bibliography consulted, of the irrelevance in the use of insulation (if not of its inconvenience). Then, it seems pertinent to make a new study on the thermal conditions throughout the 24 hours of a specific day, in the case of the implementation of insulation in the external enclosures. The 17th of January was selected as a representative day in winter conditions, and the 23rd of July as a representative of summer. Both das are characterized by the regular oscillation of the external temperature in them [4, 5]. Among the main conclusions of the research carried out can be highlighted: - When the perimeter insulation of the external enclosures is considered, the maximum temperatures are up to 6ºC below the maximum external temperature. As the damping of the internal thermal wave is high and the amplitudes are very low, there is a very important stability of the internal temperature of the dwelling when this insulation is implemented. - From the analysis carried out it can be deduced that the typical thickness of the insulation is 4 cm, in correspondence with the specifications of the Cuban Standard NC 220-1: 2009 for the insulation of roofs. - The perimeter insulation together with a possible shading of the openings provides in winter an indoor temperature almost constant throughout the 24 hours of the day at around 22ºC. Which represents a clear improvement compared to the absence of insulation. In such a case a normal ventilation level is enough. - In the summer, with perimeter insulation and possible shading of the openings, the minimum indoor temperature is only 2ºC higher than the minimum outdoor temperature. This provides an average indoor temperature close to 26ºC, in a clearly a comfortable situation. In this case, a medium-high ventilation level is preferable, although not crucial. - As a main conclusion it can be stated that a solution with the implementation of 4 cm of perimeter insulation combined with solar protection of the external hollows confers the dwelling a very good level of comfort to the warm-humid climate, both in winter and in summer. Being not necessary but appropriate an additional level of ventilation
[en] The paper compares the natural radioactivity and radon emission properties of different building materials like bricks, concretes, cements, sands, limes, marmors of different origin. A description of the radioactive model of apartments is also given. (TRA)
[en] Jung is responding to the challenge of energy efficiency, ease of operation and economic profitability in all of its solutions for the tertiary sector, whether for newly constructed buildings or refurbishments, for full management of the electrical system or the partial control of lighting, HVAC, mood settings, access control, etc., for the bedrooms or specific areas of the building. In the specific case of hotels, Jung offers each a custom-made solution in line with its possibilities and objectives. (Author)
[en] Mobility has now a crucial requirement for wireless communication. Handover is one of the major tasks that are used to support continuous transmission for a mobile terminal into different radio coverage area. Optimizing the existing handover protocol requires integrating new functionalities. This work focuses on presenting and optimizing handover algorithm. We analyze handover time in wireless local area networks based on the IEEE 802.11b MAC protocol. In fact, scan phase is the main contributor to the handover time. Then, we propose a handover model which replaces a scan phase by a positioning process. This model is able to select the suitable access point (AP) based on the shortest distance far from the mobile terminal (MT). Proposed Handover allows a mobile user to reacting quickly to decide about to which access point to connect. Simulation results show that the proposed model provides gains in term of delays and Handover success in various scenarios.
[en] In this paper, we address the issue of conducting a sensitivity analysis of complex models with both static and dynamic uncertain inputs. While several approaches have been proposed to compute the sensitivity indices of the static inputs (i.e. parameters), the one of the dynamic inputs (i.e. stochastic fields) have been rarely addressed. For this purpose, we first treat each dynamic as a Gaussian process. Then, the truncated Karhunen–Loève expansion of each dynamic input is performed. Such an expansion allows to generate independent Gaussian processes from a finite number of independent random variables. Given that a dynamic input is represented by a finite number of random variables, its variance-based sensitivity index is defined by the sensitivity index of this group of variables. Besides, an efficient sampling-based strategy is described to estimate the first-order indices of all the input factors by only using two input samples. The approach is applied to a building energy model, in order to assess the impact of the uncertainties of the material properties (static inputs) and the weather data (dynamic inputs) on the energy performance of a real low energy consumption house. - Highlights: • Sensitivity analysis of models with uncertain static and dynamic inputs is performed. • Karhunen–Loève (KL) decomposition of the spatio/temporal inputs is performed. • The influence of the dynamic inputs is studied through the modes of the KL expansion. • The proposed approach is applied to a building energy model. • Impact of weather data and material properties on performance of real house is given
[en] The optimum maintenance of installations in hotel establishments is becoming increasingly necessary given the complexity and diversity of this type of buildings, with the aim of being efficient in the use of the resources that they consume, such as water and energy. From the owners of the establishments and the companies responsible for the hotel management, to the clients that stay in them, it is vitally important that the operation of its installations is guaranteed at all times, particularly as regards temperature control. Proper preventive maintenance therefore plays an essential role in ensuring that the hotel guests’ experience is as positive as possible. (Author)
[en] The Royal Academia of Fine Arts of San Fernando (RABASF) is a royal founding institution created in 1752 with the authority of: Introduce a new style, the neoclassicism. Teach the three nobles arts, painting, sculpture and architecture. Issue the differents degrees.
[en] It is shown that the method for testing power cables for the absence of ignition presented in Circular Ts-02-98 does not allow for the effect of thermal decline of the current, which leads to overestimation of the cross section of the chosen cables, especially in 0.4-kV networks. It is recommended to equip house cable networks of power objects with long-range backup protections
[en] Several epidemiological studies have based their estimates of magnetic field exposure on the proximity to power lines. This has been done in three principally different ways, which differ in the amount of information that is used. These are: (1) distance; (2) distance and configuration (wire code); and (3) distance, configuration, and load (calculated field). It is presumed that the more information that is used, the more accurate is the exposure estimate. All these three approaches suffer from the limitation that they only account for exposure that is generated by power lines. The influence on the in-home magnetic field from sources other than the power line are not considered, nor is exposure experienced at places other than the home. This raises the following question. What is the implication for the result of the epidemiological study of the exposure misclassification that is introduced by basing magnetic field exposure estimation on power lines near homes? Although the necessary information is only partly at hand the answers to this question will be discussed. The basis will be some general epidemiological principles combined with data from a Swedish study on residential exposure and cancer risk. (author)