Determination of Capillary Conductivity Coefficient by Using Electromagnetic Microwave Radiation

2016 ◽  
Vol 861 ◽  
pp. 231-238
Author(s):  
Monika Manychová ◽  
Ondřej Fuciman
Keyword(s):  
Microwave Radiation ◽  
Building Materials ◽  
Material Parameter ◽  
Construction Material ◽  
Physical Parameters ◽  
Building Structures ◽  
Building Structure ◽  
Gaseous State ◽  
Internal Cavities

Moisture in building structures affects negatively construction material physical properties, particularly thermally insulation properties. The porous structure of most building materials distinguishes by the ability to absorb water in liquid and gaseous state into its internal cavities, to fill the accumulative space of pores, to transport moisture and to re-transmit to the surroundings. The moisture characteristics of building materials are the base for evaluation of building structure thermal insulation properties. The moisture spreading via capillary conduction is the most significant material parameter of a moisture appraisal. However, it is necessary to incorporate also spreading the liquid phase into the moisture appraisal for certain structure material compositions. The article deals with determination of capillary conductivity coefficient by using electromagnetic microwave radiation. The radiation passed through a wet sample is detected and then the value of capillary conductivity coefficient is determined. The coefficient of capillary conductivity is property dependent on several physical parameters, but primarily on the moisture.

Use of EMW Radiation in the Building Industry

2014 ◽  
Vol 1041 ◽  
pp. 297-302 ◽  
Author(s):  
Miloslav Novotný ◽  
Karel Šuhajda ◽  
Jindřich Sobotka ◽  
Jan Gintar
Keyword(s):  
Moisture Content ◽  
Electromagnetic Radiation ◽  
Microwave Radiation ◽  
Building Materials ◽  
Building Industry ◽  
Water Molecules ◽  
Building Structures ◽  
Moist Material ◽  
Modern Times ◽  
Radiation Sources

This paper discusses theory and application of microwave radiation and experimental optimization of microwave radiation to eliminate moisture content in wood elements. Owing to its properties, microwave radiation has been used in the construction industryin modern times, in particular to dry wet masonry of buildings. Effects of electromagnetic radiation on building structures lead to relatively sharp decreases in moisture content from damp building structures or elements. The influence of electromagnetic radiation on building structures lead to oscillation of water molecules contained in the material, which cause a phase transformation of water into vapour. Consequently, the vapour evaporates from the moist material, thereby drying the element exposed to radiation.The article describes experiments carried out at the Faculty of Civil Engineering of the Faculty of Technology in Brno that demonstrate successful decrease of water content in building materials using microwave radiation. First, the understanding of microwave radiationwill be discussed.Following an analysis of research results an optimum intensity of microwave radiation sources as well as the necessary length of the irradiation of microwave radiation have been determined with respect to the particular type of building material and the success rate of elimination of moisture.

scholarly journals Features of the design of structures in the conditions of Mars

2020 ◽  
Vol 26 (5) ◽  
pp. 73-89
Author(s):  
А.S. Bilyk ◽  
◽  
I.V. Hrebenieva ◽  
Keyword(s):  
Life Cycle ◽  
Negative Impact ◽  
Effective Means ◽  
Physical Parameters ◽  
Building Structures ◽  
Project Proposal ◽  
Human Needs ◽  
Research Mission ◽  
Wide Range

The article discusses the basic physical parameters and climatic features of Mars as a possible site for the construction of the first stationary research mission. They are the main factors of influence in the development of building structures for this planet. The analysis includes existing project proposals for buildings on Mars and effective means of protecting them against the negative impact of the environment, taking into account the experience of construction in complicated conditions on Earth. The detailed analysis of data allowed us to determine the parameters for the choice of location for building a colony. The parameters include soil composition, climatic indicators, terrain, level of cosmic radiation, methane fluctuations places, the equator zone, promising places for research, and successful landing places of the previous missions. Based on this, we justified the choice of the building complex location, which is the decisive factor for construction. An important aspect is also the determination of the planet colonization stages and the building requirements based on the needs of the colony. A project proposal has been developed for the second stage of planetary colonization. A colony is a quasi-closed system with its own “life cycle”, consuming only its own resources and available resources of the planet. The viability parameters of the project determine the full colony “life cycle”. We propose the hierarchical system of functions of the research mission complex. It includes five main functions: research, transport, residential, production, and recycling. The principle of hierarchy is used for the development of functional parameters of premises and the determination of links between them. In general, three blocks can be distinguished: residential, scientific, technical, and warehouse, which is organically interconnected. The system of functions is maximally optimized for human needs in Martian conditions and is designed to integrate artificial intelligence into the colony. However, the problems considered in the article are only a part of a wide range of technical, transport, financial, and other tasks that make up the range of issues of Mars development.

scholarly journals Moisture Transfer in Concrete: Numerical Determination of the Capillary Conductivity Coefficient

2017 ◽  
Vol 25 (1) ◽  
pp. 10-18 ◽  
Author(s):  
Elie Simo ◽  
Pascal Durant Dzali Mbeumo ◽  
Jeanne Claude Mbami Njeuten
Keyword(s):  
Building Materials ◽  
Moisture Transfer ◽  
Small Time ◽  
Moisture Distribution ◽  
Physical Parameters ◽  
Time Interval ◽  
Time Intervals ◽  
Fifth Order ◽  
Cellular Concrete

Abstract We numerically investigated moisture transfer in buildings made of concrete. We considered three types of concrete: normal concrete, pumice concrete and cellular concrete. We present the results of a 1-D liquid water flow in such materials. We evaluated the moisture distribution in building materials using the Runge-Kutta fourth-and-fifth-order method. The DOPRI5 code was used as an integrator. The model calculated the resulting moisture content and other moisture-dependent physical parameters. The moisture curves were plotted. The dampness data obtained was utilized for the numerical computation of the coefficient of the capillary conductivity of moisture. Different profiles of this coefficient are represented. Calculations were performed for four different values of the outdoor temperature: -5°C, 0°C, 5°C and 10°C. We determined that the curves corresponding to small time intervals of wetting are associated with great amplitudes of the capillary conductivity . The amplitudes of the coefficient of the capillary conductivity decrease as the time interval increases. High outdoor temperatures induce high amplitudes of the coefficient of the capillary conductivity.

scholarly journals Experimental and theoretical approach to determination of heat evolution in electrically conductive aluminosilicates

2020 ◽  
Vol 24 (2 Part A) ◽  
pp. 787-794
Author(s):  
Lukas Fiala ◽  
Jiri Madera ◽  
Robert Cerny
Keyword(s):  
Building Materials ◽  
Heat Evolution ◽  
Limiting Factor ◽  
Mechanical And Thermal Properties ◽  
Building Structures ◽  
Electrically Conductive ◽  
Voltage Level ◽  
Self Heating ◽  
Electric Source

Design of progressive building materials with increased utility value is the key issue for the development of reliable modern building structures. Compared to the conventional materials, progressive building materials are supposed to exhibit not just adequate mechanical, and thermal properties, but they are also supposed to be applicable in sophisticated solutions, such as in self-sensing, self-heating or magnetic-shielding systems. In terms of electric properties, the most of building materials are electric insulators which is the main limiting factor for their applicability in such sophisticated solutions. However, this deficiency can be solved by the addition of a proper amount of electrically conductive admixtures. Within the paper, electrically conductive alkali-activated aluminosilicate with 8.89 mass.% of carbon black admixture was designed and its materials properties necessary for calculations of heat evolution by the action of an electric source were experimentally determined. The electrical conductivity of such material equal to 5.57?10?2 S m?1 was sufficiently high to ensure self-heating ability. It was observed good agreement of experimentally determined data with those modeled by means of heat equation on sample with dimensions 40 ? 40 ? 10 mm. Finally, one- and two-layered large-scaled heating elements based on materials with experimentally determined properties were designed and calculations were conducted to determine the voltage level necessary for one-hour heating from 268.15 K and 273.15 K to 278.15 K in the middle-top point of the construction.

Pre-Decommissioning Radiological Characterization of Concrete

2007 ◽  
Author(s):  
Sven Boden ◽  
Eric Cantrel
Keyword(s):  
Building Materials ◽  
Gamma Spectroscopy ◽  
Cost Minimization ◽  
Field Tests ◽  
Building Structures ◽  
Naturally Occurring Radionuclides ◽  
Non Destructive ◽  
Activation Depth

The decommissioning of the BR3 (Belgian Reactor 3) approaches its final phase, in which the building structures are being decontaminated and either denuclearized for possible reuse or demolished. Apart from the presence of naturally occurring radionuclides in building materials, other radionuclides might be present due to contamination or activation. The overall process of the BR3 building structure D&D (Decontamination & Decommissioning) consists of the following steps: • make a complete inventory and preliminary categorize all elements based on historical data; • characterize and determine the contamination or activation depth; • determine the decontamination method; • perform the decontamination and clean up; • a possible intermediate characterization followed by an additional decontamination step; and • characterize for clearance. A good knowledge of the contamination and activation depth (second step) is fundamental in view of cost minimization. Currently, the method commonly used for the determination of the depth is based on core drilling and destructive analysis. Recently, we have introduced a complementary non destructive assay based on in-situ gamma spectroscopy. Field tests at BR3, both for contamination and activation, showed promising results.

DETERMINATION OF PERFORMANCE INDICATORS OF THE TRUCK KrAZ-6510TE

2020 ◽  
pp. 19-26
Author(s):  
Olexandr Pavlenko ◽  
Serhii Dun ◽  
Maksym Skliar
Keyword(s):  
Mathematical Model ◽  
Surface Friction ◽  
Building Structures ◽  
Maximum Torque ◽  
Military Equipment ◽  
Military Vehicles ◽  
Force Magnitude ◽  
Vehicle Mobility ◽  
The Mathematical Model

In any economy there is a need for the bulky goods transportation which cannot be divided into smaller parts. Such cargoes include building structures, elements of industrial equipment, tracked or wheeled construction and agricultural machinery, heavy armored military vehicles. In any case, tractor-semitrailer should provide fast delivery of goods with minimal fuel consumption. In order to guarantee the goods delivery, tractor-semitrailers must be able to overcome the existing roads broken grade and be capable to tow a semi-trailer in off-road conditions. These properties are especially important for military equipment transportation. The important factor that determines a tractor-semitrailer mobility is its gradeability. The purpose of this work is to improve a tractor-semitrailer mobility with tractor units manufactured at PJSC “AutoKrAZ” by increasing the tractor-semitrailer gradeability. The customer requirements for a new tractor are determined by the maximizing the grade to 18°. The analysis of the characteristics of modern tractor-semitrailers for heavy haulage has shown that the highest rate of this grade is 16.7°. The factors determining the limiting gradeability value were analyzed, based on the tractor-semitrailer with a KrAZ-6510TE tractor and a semi-trailer with a full weight of 80 t. It has been developed a mathematical model to investigate the tractor and semi-trailer axles vertical reactions distribution on the tractor-semitrailer friction performances. The mathematical model has allowed to calculate the gradeability value that the tractor-semitrailer can overcome in case of wheels and road surface friction value and the tractive force magnitude from the engine. The mathematical model adequacy was confirmed by comparing the calculations results with the data of factory tests. The analysis showed that on a dry road the KrAZ-6510TE tractor with a 80 t gross weight semitrailer is capable to climb a gradient of 14,35 ° with its coupling mass full use condition. The engine's maximum torque allows the tractor-semitrailer to overcome a gradient of 10.45° It has been determined the ways to improve the design of the KrAZ-6510TE tractor to increase its gradeability. Keywords: tractor, tractor-semitrailer vehicle mobility, tractor-semitrailer vehicle gradeability.

Resistance of Binding Systems of Various Compositions to the Action of Molds

2020 ◽  
Vol 786 (11) ◽  
pp. 41-46
Author(s):  
V.V. STROKOVA ◽  
◽  
V.V. NELUBOVA ◽  
M.N. SIVALNEVA ◽  
M.D. RYKUNOVA ◽  
...  
Keyword(s):  
Aging Process ◽  
Building Materials ◽  
Environmental Safety ◽  
Fungal Resistance ◽  
Building Structures ◽  
Vital Activity ◽  
Regulatory Documents ◽  
Living Organisms ◽  
Biological Corrosion ◽  
Test Objects

The dynamic development of urbanization contributes to an increase in emissions of industrial waste, which is the cause dysfunction of the ecosystem balance and leads to the development of biological corrosion on building materials associated with the products of the vital activity of microorganisms. In this regard, it is necessary to assess the resistance of composites to predict the durability of building structures under conditions of biological influence of microorganisms. Binder systems of various compositions were studied: cementless nanostructured binders (NB) based on quartz sand and granodiorite, gypsum, Portland cement and alumina cement. The toxicity of binders was assessed by biotesting on living organisms – cladocerans Daphnia Magna – according to the criteria of the intensity of their growth and viability. As a result, the high environmental safety of NB is substantiated, and the ranking of the studied binders according to the degree of increase in their toxicity to test objects is presented. Fungal resistance was assessed by the ability of molds for growing and reproduction on the studied samples. It was found that the most active in terms of the development of binders were representatives of the genus Aspergillus, the intensity of growing of which in all variants did not decrease below 3 points. Gypsum and NB were especially vulnerable, where the degree of fouling repeatedly reached 5 points. Even the initially biostable cement, after the aging process, lost its stability at different extent. The obtained results indicate the need to increase the resistance of composites for various purposes under conditions of biocorrosion at the stage of design and updating of regulatory documents, including tests for fungal resistance in the list of mandatory.

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