Experimental Assessment of the Effects of Building Materials on Wi-Fi Signal 2.4 GHz and 5 GHz

We are all witnesses to the widespread use of wireless LANs (WLAN) and their easy implementation in indoor environments. Wi-Fi is the most popular technology for the WLAN. However, interference caused by building materials is a common, yet often overlooked, contributor to poor Wi-Fi performance. This interference occurs due to the nature of radio wave propagation and the characteristics of the wireless communication system. Therefore, during the implementation of these networks, one must consider the quasi-static nature of the Wi-Fi signal and its dependence on the influence of various building materials on the propagation of these waves. This paper presents the effects of building materials and structures on indoor environments for Wi-Fi 2.4 GHz and 5 GHz. To establish the interdependencies between factors influencing electric field levels, measurements were conducted in an experimental Wi-Fi network at different distances from the access point (AP). The results obtained show that the electric field strength of the Wi-Fi signal decreases depending on the distance, the building materials, and the transmitted frequency. Concrete material had the most significant impact on the strength of the electric field in Wi-Fi, while glass had a relatively minor effect on reducing it. Wi-Fi operates within the radio frequency spectrum, typically utilizing frequencies in the 2.4 GHz and 5 GHz bands. Additionally, measurements revealed that Wi-Fi signal penetration is more pronounced at lower frequencies (2.4 GHz) as opposed to the Wi-Fi signal 5 GHz. The findings can be used to address the impact of building materials and structures on indoor radio wave propagation, ultimately ensuring seamless Wi-Fi signal coverage within buildings.

Comparative Study of Two Materials Combining a Standard Building Material with a PCM

Phase change materials(PCMs)have the ability to store thermal energy and make it available at a later stage to keep indoor temperature within a specific range and achieve better thermal comfort in buildings.This study focuses on the performances of materials obtained by combining a standard building material with a PCM.In particular,two different materials mixed with the same PCM are considered under the same climatic conditions.The related thermal behavior is assessed in the framework of numerical simulations conducted with ANSYS Fluent assuming parameters representative of a city located in Europe.The results show that the addition of PCM to concrete and bricks can improve the thermal inertia of the resulting material.

Analysis of the Performances of a New Type of Alumina Nanocomposite Structural Material Designed for the Thermal Insulation of High-Rise Buildings

The sol-gel method is used to prepare a new nano-alumina aerogel structure and the thermal properties of this nanomaterial are investigated comprehensively using electron microscope scanning,thermal analysis,X-ray and infrared spectrometer analysis methods.It is found that the composite aerogel alumina material has a multi-level porous nano-network structure.When employed for the thermal insulation of high-rise buildings,the alumina nanocomposite aerogel material can lead to effective energy savings in winter.However,it has almost no energy-saving effect on buildings where energy is consumed for cooling in summer.

Summary of Research on Use of Sediment in Building Materials

Based on the recent research at home and abroad,this paper summarizes the preparation of cement clinker,baking-free brick,subgrade filler and ceramsite from sediment,and puts forward relevant suggestions and prospects for the future research direction of sediment.

Thermomechanical and Hydrous Effect of Heavy Fuel Oil in a Building Material Based on Silty Clayey Soil

This study focuses on the use of heavy fuel oil in construction in Burkina Faso.Mixed with silty and/or clay soil,it is used as a coating to reinforce the walls of raw soil constructions which are very sensitive to water.The interest of this paper is to shed light on the thermomechanical and above all water effects of heavy fuel oil on a sample of silty clayey soil.To achieve this,we used heavy fuel oil added in different proportions to silty clayey soil,to make sample of bricks on which tests were carried out.At the end of the experimental tests carried out on materials made(bricks)with our soil sample,it appears that heavy fuel oil moderately reduces the mechanical resistance of bricks and slightly increases thermal diffusion through them.On the contrary,we note a very good water resistance of the bricks thanks to the heavy fuel oil,in particular their water absorption by capillarity.This confirms that the mixture of heavy fuel oil and a silty-clayey soil used as a coating makes it possible to prevent the infiltration of water into the walls of raw soil constructions.However,its use as a construction material does not guarantee very good mechanical resistance,and slightly increases thermal diffusion.

Material Analysis of Traditional Folk Dwellings and Its Modern Inheritance:A Case Study of Traditional Folk Dwellings in Hunan Province

Traditional folk dwellings contain rich cultural connotations and plain architectural techniques.In architecture,material is the most fundamental thing,different materials can demonstrate different architectural forms,and reflect local characteristics and change of the time.Therefore,it is of great significance to explore the material selection of traditional Chinese folk dwellings.The paper took traditional folk dwellings in Hunan for example to analyze the regional materials and construction of these dwellings,discussed the application of traditional materials in modern architecture,used some cases to explore the innovative application of traditional materials,so as to figure out the new direction of applying traditional materials,and provide references for the construction of modern architecture.

Numerical Modelling of Coupled Heat and Mass Transfer in Porous Materials: Application to Cinder Block Bricks

In this work, we present numerical modelling of coupled heat and mass transfer within porous materials. Our study focuses on cinder block bricks generally used in building construction. The material is assumed to be placed in air. Moisture content and temperature have been chosen as the main transfer drivers and the equations governing these transfer drivers are based on the Luikov model. These equations are solved by an implicit finite difference scheme. A Fortran code associated with the Thomas algorithm was used to solve the equations. The results show that heat and mass transfer depend on the temperature of the air in contact with the material. As this air temperature rises, the temperature within the material increases, and more rapidly at the material surface. Also, thermal conductivity plays a very important role in the thermal conduction of building materials and influences heat and mass transfer in these materials. Materials with higher thermal conductivity diffuse more heat.

Industrial TiO2 based nacreous pigments as functional building materials:Photocatalytic removal of NO

In this paper,the photocatalytic activity of industrial titanium dioxide(TiO2)based nacreous pigments was researched as functional building materials for photocatalytic NO remove.Three industrial TiO2 based nacreous pigments were selected to estimate the photocatalytic activity for NO remove.This study is a good proof that pearlescent pigments can eliminate NO,and its performance is positively correlated with its titanium dioxide content.And this research will widen the application of nacreous pigments in functional building materials,and provide a new way to eliminate in door nitric oxide pollution.

Enhanced Thermal Performance of Roofing Materials by Integrating Phase Change Materials to Reduce Energy Consumption in Buildings

This work focused on characterizing and improving the thermal behavior of metal sheet roofing.To decrease the heat transfer from the roof into a building,we investigated the efficiency of four types of phase change materials,with different melting points:PCMІ,PCM II,PCM III and PCM IV,when used in conjunction with a sheet metal roof.The exterior metal roofing surface temperature was held constant at 50℃,60℃,70℃and 80℃,using a thermal source(halogen lights)for 360 min to investigate and compare the thermal performance of the metal sheet roofing with and without phase change materials for each condition.The thermal behaviors of the phase change materials were analyzed by differential scanning calorimeter(DSC).The results showed the melting points of PCMІ,PCM II,PCM III and PCM IV were around 45℃,50℃,55℃and 59℃,respectively.The integration of PCM IV into the metal roofing sheet increased the thermal performance by reducing the room temperature up to 2.8%,1.4%,1.0%and 0.7%when compared with the normal metal roof sheet,at the controlled temperatures of 50℃,60℃,70℃and 80℃,respectively.The thermal absorption of the phase change materials also caused a time delay in the model room reaching a steady temperature.The integration of phase change materials with metal roofing sheets resulted in better thermal performance and conservation of electrical energy by reducing the demand for cooling.

Carbon foams prepared from coal tar pitch for building thermal insulation material with low cost

A new approach is provided to resolve the large-scale applications of coal tar pitch. Carbon foams with uniform pore size are prepared at the foaming pressure of normal pressure using coal tar pitch as raw materials. The physical and chemical performance of high softening point pitch(HSPP) can be regulated by vacuumizing owing to the cooperation of vacuumizing and polycondensation. Results indicate that the optimum softening point and weight ratio of quinoline insoluble are about 292℃ and 65.7%, respectively. And the optimum viscosity of HSPP during the foaming process is distributed in the range of 1000-10000 Pa·s. The resultant carbon foam exhibits excellent performance, such as uniform pore structure, high compressive strength(4.7 MPa), low thermal conductivity(0.07 W·m^(-1) ·K^(-1)), specially, it cannot be fired under the high temperature of 1200 ℃.Thus, this kind of carbon foam is a potential candidate for thermal insulation material applied in energy saving building.

Exploration on the Recycling of Waste Building Materials in Comprehensive Land Consolidation from the Perspective of Ecological Civilization

The necessity and difficulties of waste building material utilization in comprehensive land consolidation are put forward by analyzing the source,quantity and harm of waste building materials.Combined with the practice of Shanghai,the mechanism and pattern of waste building materials recycling are explored,in order to provide the reference for recycling of waste building materials and efficient promotion of land consolidation.

Training Strategies of Practical Ability of Building Materials Professionals in Higher Vocational Colleges Under the Guidance of“Three Education Reform”Concept

The main purpose of the implementation of the three-education reform concept is to improve the teaching quality and talent training level of higher vocational colleges.Through the reform,one can promote the optimization of teaching methods,provide more space for student’s self-development,and improve the quality of talent training.Building materials in higher vocational colleges are a high requirement for practical ability,which emphasizes the cultivation of students’practical ability.Under the three-education reform concept,the traditional teaching mode should be replaced to provide more practical opportunities for students,in return give more attention to the development of students’practical ability.This paper mainly explores the current situation and training strategies in building material professionals in higher vocational colleges under the reform of the three education systems for a reference.

Modeling Water Adsorption and Retention of Building Materials From Pore Size Distribution

Water adsorption and capillarity are key phenomena involved during heat and moisture transfer in porous building materials.They account for interaction between solid matrix,liquid water and moist air.They are considered through Water Vapor Adsorption Isotherm(WVAI)and Retention Curve(RC)functions which are constitutive laws characterizing water activity within a porous medium.The objective of this paper is to present a water vapor adsorption and retention models built from multimodal Pore Size Distribution Function(PSDF)and to see how its parameters modify moisture storage for hygroscopic and near saturation ranges.The microstructure of the porous medium is represented statistically by a bundle of tortuous parallel pores through its PSDF.Firstly,the influence of contact angle and temperature on storage properties were investigated.Secondly,a parametric study was performed to see the influence of the PSDF shape on storage properties.Three cases were studied considering the number of modalities,the weight of each modality and the dispersion around mean radius.Finally,as a validation,the proposed model for WVAI were compared to existing model from literature showing a good agreement.This study showed that the proposed models are capable to reproduce various shapes of storage functions.It also highlighted the link between microstructure and adsorption-retention phenomena.

Running States of China's Iron & Steel,Nonferrous,and Building Materials Industries in 2012

Iron ＆ Steel Industry China＇s outputs of crude steel, steel products, coke and ferrous alloys in 2012 were 716.54 million tons （up 3.1% YOY）, 051.86 million tons （up 7.7% YOY）, 443.23 million tons （up 5.2% YOY） and 31.29 million tons （up 15% YOY）,

A Brief Analysis of Energy Conservation Ways by Building Materials for Ecological Architecture

The development of society and economy in China is bringing growth to all industries. In particular, the development of China’s building industry has attracted much attention. Building materials are an important part of and widely used in the building industry. Energy conservation by building materials has become an inevitable way of sustainable development. Centering on the building industry, this paper mainly discusses in detail the energy conservation ways by ecological architecture and building materials.

Multi-criteria Decision of Type and Building Material for Simple House Construction

Facing the innovation technology in building construction, the designer has the option in selecting the type of system construction and building materials. There is a big question for the designer and owner on how to evaluate the quality material to meet the technical requirements as building construction reliability. By demand to provide a low cost house, there is need for improving structure model and material construction for residents. When material cost takes 60%-70% of total construction cost, it is important to select the appropriate building material. Currently the innovation of material building for main frame and wall component has present for residential projects in Indonesia. Attempt to replace the traditional material such as brick or pozzolan lime concrete block is developed a new material include utilization of coal combustion waste for concrete block, lightweight concrete, or prefab panel wall. This paper presents the research result to develop a tool support for material and system construction selecting that facilitates the selection an optimal material for a simple house construction. A multi-criteria decision method is used based on performance criteria such as economy, reliability, comfort and eco-friend.

Natural Radioactivity Measurements for Some Algerian Building Materials

The objective of this work is to assess the radiation hazards associated gamma rays from building materials. Natural gamma rays activities of natural radionuclide represented mainly by three natural radioactive series ^238U, ^235U and ^232Th, and the primordial ^40K in the samples of building materials which consist of bricks, ceramics, marble and gypsum from different areas of eastern Algeria are measured using gamma ray spectrometry. The values of the activities of these radionuclides do not clearly reflect the radiation hazard associated with these materials. Therefore, the radium equivalent （Raeq） concentration is defined taking into account the effectiveness of these isotopes in creating the radiation hazard. Radium equivalent activities, external and internal hazard indices （Hex and Hin） are calculated from the activities of ^226Ra, ^232Th and ^40K for suitability of the materials.

China's Building Materials Industry

China’s building materials industry experienced great development in 1993 with rapid increases in production and record output and profits. The industry produced 360 million tons of cement, 96.163 million cases of plate glass, 20.4 million pieces of sanitation ceramics and 173 million square metres of construction ceramics, showing rises of 12.89, 12.83, 123.8 and 127 percent respectively over the previous year. The output of cement and

1989 12 Good Building Material Products Won State Awards in China

In 1989, there were 12 different building ma-terial products winning state awards for theirgood quality, among which two got gold medals andten got silver medals.