The objective of the paper is to describe the problem of regulating the thermal power in a central heating installation through a sequential combination of quantitative thermal adjustment (flow of thermal agent) with qualitative thermal adjustment (temperature of the thermal agent). The general thermal adjustment relationships are presented based on which the possibility of combining the two types of thermal adjustment is established. The quantitative thermal adjustment is performed until the thermal agent flow is reduced by a maximum of 50% of the nominal value.The result obtained is presented graphically and commented.

The paper presents a method for solving the steady-state heat transfer problem through a non-homogeneous / multilayered cylindrical shell having one or all layers with variable thermal conductivity. The Solver tool from Microsoft Excel® software application is used for solving the system of nonlinear equations directly dependent on the unknown temperatures on the bounding surfaces of the layers.

In this paper, two types of heat exchangers specific to the building service systems are studied: the arborescent thermal networks that supply the central heating and domestic hot water preparation systems inside the urban buildings, respectively the heat exchangers connected in loops designed for solar energy use. The paper presents the procedures for determining the thermal characteristics (the number of transfer units, NTU and the so-called thermal module, E) that can be used for evaluating the heat flow transfer within the mentioned equipments.

For the present study it was desired to analyze nine models of structures, the difference between them being the height and the height regime. Structural modeling was carried out with the help of the ETABS program, carrying out a series of studies for buildings with a structure from b.a. (respectively double frames) - buildings with square shape in plan (with 3 height regimes: B+15, B+10, B+5), rectangular shaped building in plan (with 3 height regimes: B+15, B+10, B+5), round shaped plan building (with 3 height regimes: with 3 height regimes: B+15, B+10, B+5), the embedding of the superstructure considering at the level of the floor above the basement 1. Also, models of calculation with the same types of buildings were made, taking into account the classical modeling ofthe land-structure interaction as well as models of calculation with the same types of buildings, taking into account consideration of base isolation, with two types of basic seismic isolators (LRB and HDRB). Comparisons were made between all the structural calculation models used.

This work deals the rheological and mechanical behavior of metallurgical cements based on nano-silica (NS) combined with blast furnace slag (GBFS). An experimental study was conducted with constant water-to-binder ratio (W / B) of 0.5 used for all studied mortars. In order to use the max of GBFS and decrease the consumption of cement, the different contents (36% and 66%.wt) of GBFS and 3%.wt of NS were chosen and added to Portland Cement (PC). Rheological tests were conducted on cementitious pastes and mechanical tests were carried on mortars elaborated with metallurgical cement studied. Obtained results show that that cementitious pastes with 3% NS without GBFS were the least viscous and have a lower shear stress with acceptable workability compared to other cement pastes. However, in the presence GBFS the cement pastes become more viscous which makes the flow more difficult with higher shear stress at the flow. Also, the results showed in comparison with the GBFS control mortars that the incorporation of a small amount of NS in the cement in the presence of GBFS remarkably increases the compressive strength at 28 and 90 days. Incorporation of 3% wt NS in cement pastes with a 36% and 66% wt GBFS content gave respectively very high 90 day compressive strength values (71.70 and 56.30 MPa). NS and LHF can remarkably reduce the porosity of the cement matrix, and increase the density of the latter, which also explains the high resistance of the compressive strength.

In this study is presented, on the one hand, the complexity of the phenomenon of flashover, and on the other hand, a number of methods for estimating the main parameters of this phenomenon. The moment of the flashover phenomenon is quite difficult to predict by incoming crews at the site of the intervention. It presents a special hazard for both the occupants of the fire building and the intervention forces, due to the fact that, during this phenomenon, the value of the temperature inside the compartment reaches 500-600 ° C, and the density of the heat flow emitted from the fire, at the level of the compartment floor, at about 20 kW/m2. Also, three methods were used to estimate, with FDTs, the rate of heat rate released by the fire during the phenomenon of flashover, a method of estimating the temperature of the fire compartment in the post-flashover phase, respectively, a method of estimation of the fire severity.

This paper evaluate the flexural–shear behaviour of reinforced concrete beams strengthening by embedded carbon fiber reinforced polymer grids (CFRP grids) and metallic grids with hexagonal meshes, under four-point bending test. An experimental investigation was carried out to evaluate the performance of this new technical of strengthening, Three control beams and fifteen beams strengthened in flexural–shear with different configurations have been tested. Several parameters were considered to highlight the efficiency of the technical used, such as; ultimate load, ductility and failuremodes. The experimental results show that the beams strengthening by embedded carbon and metallic grids offered a great improvement in strength, midspan deflection and ductility index; in effect, an influence directly on the failure mode is observed.

Exploitation of unsaturated soil permeability data (ku) in some cases requires that this characteristic be estimated by methods not measured by laboratory tests and in this case, it is best to use mathematical models to evaluate this parameter. Evaluation of the unsaturated permeability using different estimation methods as well as the studies of comparisons between the results of these models for different types of soils have been treated by several authors ([1], [2]), however none of these authors have compared the results of these models for identical soils (same type of soil, same extraction site, same percentage of different constituents, ect...). In this article we have presented the views of the authors who have treated this subject, then, we applied some models of estimation of ku to samples of sand and silty clay. Also we took as a special case, identical samples that have been extracted from the SoilVision 003 database [3]. After applying to these samples the models of Kunze & al [4], Campbell [5] and Brooks & Corey [6], we found that all these models can present divergent predictions for samples of the same type of soil and also for identical samples. We deduced therefore that there is no general rule that allows us to choose between ku prediction models and that it is always mandatory to go through a series of comparisons in order to select the model that best applies to a soil sample.

Floods caused by rivers areone of the serious, common and natural disasters that many countries are facing. It has caused an immense damage, and a huge proportion of such destruction is associated with the lack of knowledge, resources and coping mechanisms. Therefore, studies and researches on the nature of the rivers are inevitable. Computer models are an effective tool for studying and simulating river behavior with the least possible cost, and one of the measures for the risk reduction is the delineation of flood-prone areas. Flood risk mapping involves modeling the complex interaction of the river flow hydraulics with topographical and land use features of the floodplains. An integrated approach to river flood modeling is the use of GIS and hydraulic models. This paper presents the use of flood frequency analysis integrating with 2D Hydraulic model (HECRAS) and Geographic Information System (GIS) to prepare flood maps of different return periods: 10 years, 20 years, 50 years, and 100 years in Wadi Bougdoura; Wadi SEBAOU and Wadi Sbet at DraaBenKahada City in TiziOuzou. The resulting hydraulic model provides a good representation of the general landscape and it contains additional details, the results indicate that GIS is an effective environment for mapping and analyzing floodplains, they clearly show that this new approach, based on 2D simulation results, allows the stakeholders to have a better appreciation of the consequences of a flood, a design of making a land use and infrastructure development decisions, and emergency measures.

Reducing GHG emissions is directly linked to more efficient use of fossil fuels as an energy source to ensure thermal comfort while improving the thermal performance of building envelopes. Efforts in recent decades to improve insulation and make buildings more suitable for sealing, especially residential and tertiary sectors, must be accompanied by the elimination as far as possible of additional heat loss from thermal bridges, especially as their effect is accentuates with tire insulation. Achieving the nZEB standard developed under the Energy Performance of Buildings Directive involves constructive measures and solutions that lead to the goal set by it. In this context, the requirements established by the Romanian standards C107-2010 and Order 2641/2017 are presented, highlighting the weight played by thermal bridges. At the same time, the effect of wall insulation without a proper insulation of the balcony slab is presented, highlighting the final global effect, unexpectedly insignificant, as an example to consider in practical approaches.