Databases of 2D material-substrate interfaces and 2D charged building blocks

Discovery of materials using“bottom-up”or“top-down”approach is of great interest in materials science.Layered materials consisting of two-dimensional(2D)building blocks provide a good platform to explore new materials in this respect.In van der Waals(vdW)layered materials,these building blocks are charge neutral and can be isolated from their bulk phase(top-down),but usually grow on substrate.In ionic layered materials,they are charged and usually cannot exist independently but can serve as motifs to construct new materials(bottom-up).In this paper,we introduce our recently constructed databases for 2D material-substrate interface(2DMSI),and 2D charged building blocks.For 2DMSI database,we systematically build a workflow to predict appropriate substrates and their geometries at substrates,and construct the 2DMSI database.For the 2D charged building block database,1208 entries from bulk material database are identified.Information of crystal structure,valence state,source,dimension and so on is provided for each entry with a json format.We also show its application in designing and searching for new functional layered materials.The 2DMSI database,building block database,and designed layered materials are available in Science Data Bank at https://doi.org/10.57760/sciencedb.j00113.00188.

Progress in Resource Utilization of River Sediment in the Field of Building Materials

At present,there is a great demand for building materials in the market,and the market prospect of building materials is relatively considerable.Through studying the composition of river sediment and its resource utilization in the field of building materials,this paper expounds the current domestic scholars research on river sediment in building materials,and summarizes the current problems and challenges,so as to provide a reference for the sustainable development of river sediment in the field of building materials.

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.

Application of Environment-Friendly Building Materials in the New Countryside

Due to the high cost of environment-friendly materials and limited funds for the new countryside construction,it is the principal contradiction in the application of environment-friendly materials to satisfy the demands of both environment protection and cost reduction.The authors proposed that the influence ranking of these materials on environment should be clarified first to settle this contradiction,that is,to choose energy-conserving and environment-friendly materials within the limit of expenditure.By comparing the energy consumption,shock resistance,economic efficiency and social acceptability of wall materials,the influence ranking was given as below:hollow concrete block < lime-sand brick < baked chamotte brick;by analyzing the advantages and disadvantages of floor and roof concrete materials,as well as attentions for reducing negative impacts,the order of their influence was given as below:precast concrete trough plate < precast hollow strength concrete plate < cast-in-place concrete plate < cast-in-place brick-concrete plate;suitable materials for door and window frameworks were concluded,the influence order of wall and floor decoration materials on environment was given as:bare walls without plastering < walls of stable soil plastering < walls of cement-water plastering < walls of lime plastering;concrete for the overall decoration < parquet floor < tile floor < terrazzo floor;and 7 heat retardation materials were suggested for the construction of new countryside.

Preparation and Properties of Paraffin/PMMA Shape-stabilized Phase Change Material for Building Thermal Energy Storage

The composite phase change material(PCM) consisting of phase change paraffin(PCP) and polymethyl methacrylate(PMMA) was prepared as a novel type of shape-stabilized PCM for building energy conservation through the method of bulk polymerization. The chemical structure, morphology, phase change temperature and enthalpy, and mechanical properties of the composite PCM were studied to evaluate the encapsulation effect of PMMA on PCP and determine the optimal composition proportion. FTIR and SEM results revealed that PCP was physically immobilized in the PMMA so that its leakage from the composite was prevented. Based on the thermo-physical and mechanical properties investigations, the optimal mass fraction of PCP in the composite was determined as 70%. The phase change temperature of the composite was close to that of PCP, and its latent heat was equivalent to the calculated value according to the mass fraction of PCP in the composite. For estimating the usability in practical engineering, thermal stability, reliability and temperature regulation performance of the composite were also researched by TG analysis, thermal cycling treatments and heating-cooling test. The results indicated that PCP/PMMA composite PCM behaved good thermal stability depending on the PMMA protection and its latent heat degraded little after 500 thermal cycling. Temperature regulation performance of the composite before and after thermal cycling was both noticeable due to its latent heat absorption and release in the temperature variation processes. The PCP/PMMA phase change plate was fabricated and applied as thermal insulator in miniature concrete box to estimate its temperature regulation effect under the simulated environmental condition. It can be concluded that this kind of PCP/PMMA shape-stabilized PCM with the advantages of no leakage, suitable phase change temperature and enthalpy, good thermal stability and reliability, and effective temperature regulation performance have much potential for thermal energy storage in building energy conservation.

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.

Measurement and Monte Carlo simulation of γ-ray dose rate in high-exposure building materials

Natural radioactivity radionuclides in building materials, such as^(226)Ra,^(232)Th and^(40)K, cause indoor exposure due to their gamma-rays. In this research, in a standard dwelling room(5.0 m 9 4.0 m 9 2.8 m), with the floor covered by various granite stones, was set up to simulate the dose rates from the radionuclides using MCNP4 C code. Using samples of granite building products in Iran, activities of the^(226)Ra,^(232)Th and^(40)K were measured at 3.8–94.2, 6.5–172.2 and 556.9–1529.2 Bq kg^(-1),respectively. The simulated dose rates were26.31–184.36 n Gy h^(-1), while the measured dose rates were 27.70–204.17 n Gy h^(-1). With the results in good agreement, the simulation is suitable for any kind of dwelling places.

Natural Radioactivity Measurement and Assessment of Radiological Hazards in Some Building Materials Used in Bangladesh

The radioactivity concentrations of 226Ra, 232Th and 40K in 24 samples of natural and manufactured building materials commonly used in Bangladesh were measured using HPGe gamma ray spectrometer. The results in the present study were compared with the world average and also with the reported data available in literature. The radium equivalent activity, the absorbed dose rate, annual effective dose, external and internal hazard indices, gamma index, alpha index, annual gonadal dose equivalent and excess lifetime cancer risk were also evaluated to assess the potential radiation hazards associated with these building materials. All samples under investigation were found to be within the recommended safety limit and do not pose any significant radiation hazards. This study can be used as a reference for more extensive studies of the same subject in future.

A Multi-Criteria Decision Support System for the Selection of Low-Cost Green Building Materials and Components

The necessity of having an effective computer-aided decision support system in the housing construction industry is rapidly growing alongside the demand for green buildings and green building products. Identifying and defining financially viable low-cost green building materials and components, just like selecting them, is a crucial exercise in subjectivity. With so many variables to consider, the task of evaluating such products can be complex and discouraging. Moreover, the existing mode for selecting and managing, often very large information associated with their impacts constrains decision-makers to perform a trade-off analysis that does not necessarily guarantee the most environmentally preferable material. This paper introduces the development of a multi-criteria decision support system (DSS) aimed at improving the understanding of the principles of best practices associated with the impacts of low-cost green building materials and components. The DSS presented in this paper is to provide designers with useful and explicit information that will aid informed decision-making in their choice of materials for low-cost green residential housing projects. The prototype MSDSS is developed using macro-in-excel, which is a fairly recent database management technique used for integrating data from multiple, often very large databases and other information sources. This model consists of a database to store different types of low-cost green materials with their corresponding attributes and performance characteristics. The DSS design is illustrated with particular emphasis on the development of the material selection data schema, and application of the Analytical Hierarchy Process (AHP) concept to a material selection problem. Details of the MSDSS model are also discussed including workflow of the data evaluation process. The prototype model has been developed with inputs elicited from domain experts and extensive literature review, and refined with feedback obtained from selected expert builder and developer companies. This paper further demonstrates the application of the prototype MSDSS for selecting the most appropriate low-cost green building material from among a list of several available options, and finally concludes the study with the associated potential benefits of the model to research and practice.

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.

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.

Simulation of the Hygrothermal Behavior of a Building Envelope Based on Phase Change Materials and a Bio-Based Concrete

Phase Change Materials(PCMs)have high thermal inertia,and hemp concrete(HC),a bio-based concrete,has strong hygroscopic behavior.In previous studies,PCM has been extensively combined with many materials,however,most of these studies focused on thermal properties while neglecting hygroscopic aspects.In this study,the two materials have been combined into a building envelope and the related hygrothermal properties have been studied.In particular,numerical studies have been performed to investigate the temperature and relative humidity behavior inside the HC,and the effect of adding PCM on the hygrothermal behavior of the HC.The results show that there is a high coupling between temperature and relative humidity inside the HC,since the relative humidity changes on the second and third days are different,with values of 8%and 4%,respectively.Also,the variation of relative humidity with temperature indicates the dominant influence of temperature on relative humidity variation.With the presence of PCM,the temperature variation inside the HC is damped due to the high thermal inertia of the PCM,which also leads to suppression of moisture evaporation and thus damping of relative humidity variation.On the second and third days,the temperature changes at the central position are reduced by 4.6%and 5.1%,compared to the quarter position.For the relative humidity change,the reductions are 5.3%and 5.4%on the second and third days,respectively.Therefore,PCM,with high thermal inertia,acts as a temperature damper and has the potential to increase the moisture buffering capacity inside the HC.This makes it possible for such a combined envelope to have both thermal and hygric inertia.

Assessment of Exposure Due to Technologically Enhanced Natural Radioactivity in Various Samples of Moroccan Building Materials

The aim of our present work is to measure the specific activities of the radionuclides 226Ra, 232Th, 40K and the exhalation rates in terms of area and mass of 222Rn in some samples of building materials commonly used in Morocco in order to evaluate the radiological risk caused by natural radioactivity. To this end, the analyses were carried out, using two nuclear techniques, namely high resolution gamma spectrometry and alpha dosimetry based on the use of LR115, on 50 samples collected from large commercial suppliers in Morocco. The results of these analyses show that the average specific activities of 226Ra, 232Th and 40K in these materials vary from 9 to 52 Bq/kg, 3 to 63 Bq/kg and 68 to 705 Bq/kg respectively. These activities remain within the permissible limits of 35 Bq/kg, 30 Bq/kg and 370 Bq/kg respectively, with the exception of a few samples of red brick, gray cement, ceramic and granite. The activity of the radium equivalent (Raeq), the internal (Hin) and external (Hex) hazard indices, the absorbed dose rate, the total annual effective dose , the excess lifetime cancer risk (ELCR) as well as volumic activities, exhalation rates in terms of area (ES) and mass (EM) are calculated for the samples analyzed in this work in order to assess the radiological risks resulting from the use of these materials in various construction activities. It seems that the values of these indices vary from 19 to 196 Bq/kg, 0.08 to 0.67, 0.05 to 0.53, 9 to 91 nGy/h, 0.05 to 0.56 mSv/y, 0.19 × 10&minus;3 to 1.96 × 10&minus;3, 72 to 350 Bq/m3, 56 to 273 mBq&sdot;m&minus;2&sdot;h&minus;1 and 3 to 15 mBq&sdot;kg&minus;1&sdot;h&minus;1 respectively. The lowest values are identified for gypsum, while the highest are attributed to granite. All of the obtained results of these indices respect the permissible limits except for the Raeq in some granite samples, the ELCR index in all samples except gypsum and the radon volumic activity in some gray cement samples, ceramic and granite. As a result, the different types of building materials analyzed in our work do not present a health risk to the public and can be used in various construction activities, with the exception of a few samples of red brick, gray cement, ceramic and granite. The choice of the use of red brick, gray cement and ceramic should be monitored and adapted according to the criteria of the limitation of the doses whereas the use of the granite must be moderate in order to limit over time the health risk which increases with the duration of exposure of humans to these building materials.

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.

The Future Resources for Eco-building Materials:Ⅱ. Fly Ash and Coal Waste

To use fly ash and coal waste effectively, the current technologies for reprocessing and recycling these wastes into eco-building materials were reviewed, such as utilizing fly ash as the component of fly ash cement and low heat cement after the processes of separation, removal of carbon remains and fine comminution, calcining coal waste into kaolin and meta-kaolin with suspension technology, and preparing clinkerless alkali-activated geopolymer materials with fly ash and meta-kaolin.

Migration Effect of Temperature on Formaldehyde in Porous Building Materials

A coupled heat and formaldehyde migration model based on the non-equilibrium thermodynamic theory and molecule movement theory was developed.The effect of temperature on the transport coefficients was simulated,and the simulation results were validated with experimental data from the literatures.The calculation shows that air exchange rate larger than 2 h-1 should be prevented,if the purpose is only for formaldehyde emissions control.The effects of temperature on formaldehyde migration are obvious.

Comparison of the thermal properties of clay samples as potential walling material for naturally cooled building design

The thermal properties of different clay samples obtained from locations in Akwa Ibom State, Nigeria were investigated and compared, and in order to establish their suitability as building material from energy conservation point of view. The results showed that stoneware clay has the highest solar radiation absorptivity of 22 32 m -1 while kaolin clay has the lowest radiation absoptivity of 14 46 m -1 A model for the prediction of temperature variation with thickness of the samples was developed. Results showed that kaolin would make the best choice for the design of a naturally cooled building.

A New Type of Paper-frame Cavernous Material and Its Application in Energy Efficiency in Buildings

This paper introduces a new type of paper-frame cavernous material, which is a made-up hollow material, by using silicate-cinder size to drench and daub. It possesses excellent performances such as light-weight, high-intensity, fire-resistance, sound-insulation, heat-insulation and no-pollution. Composed with concrete materials, a new type of bearing and energy-efficient block can be gained, which is kind of excellent wall materials and has a wide application prospect.

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.

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.