Energy Efficient Materials Research Articles

Phase change materials composite boards and mortars: Mixture design, physical, mechanical and thermal behavior

Energy dependence is currently a serious problem faced by the European Union. In recent years there has been an effort to increase the use of renewable energy sources, which will allow for a sustainable increase in the energy independence of different countries. On the other hand, given the rising energy costs seen in recent years and the low income of families, energy poverty is increasingly a reality throughout Europe, especially weakening the most economically disadvantaged families. Thus, there is a need to combat this reality using renewable energies combined with functional and more energy efficient construction materials. In this study, composite boards based in mortars activated with phase change materials were developed. Initially, it was developed a study in the main properties of the PCM mortars based in the mechanical behavior, microstructure observation and thermal influence. Subsequently, PCM composite boards were developed and tested for their main physical and mechanical properties, in order to assess their possibility of inclusion in the market. Based in the results it was possible to conclude that the PCM incorporation in mortars and boards alters its properties from the physical, mechanical and thermal point of view. Regarding to the mortars characterization, there was a decrease in the flexural and compressive strength higher than 27 % and 26 % with the incorporation of non-encapsulated PCM, respectively. It was also observed a decrease in the microporosity, due to the more compact microstructure. Regarding to the thermal behavior it was verify a decrease in the maximum temperature of 6 % in summer situation and 9 % in spring season. On the other hand, there was an increase in the minimum temperature of 3 % in spring season. In the boards characterization there was an increase in the microporosity, due to the increase higher than 48 % of total porosity and 3 % in the water absorption by immersion with the PCM incorporation and a decrease in the flexural strength higher than 15 %. However, it was possible to conclude that the production of manufacturing boards based in PCM mortars can be seen as possible solution to increase the energy efficiency of buildings and decrease the energy poverty in the society.

The green design of high-rise buildings: how is the construction industry evolving

PurposeGreen building, which is also commonly referred to as sustainable building, is focused on the processes implemented that are environmentally efficient and responsible throughout the life cycle of the building. This accounts for the time of manufacturing of materials, to the erection of these materials, on-site, to the operation of the building and how these efficient materials assist in the operation and running of the building daily, all the way through to the demolition. There are many aspects of the building process that can be switched to green. For the construction industry, the change to green design although the complex is nonetheless necessary. This study thus aims to focus on supporting the knowledge surrounding green buildings in high-rise construction. This research will undertake a comparative analysis and review of one case study in Melbourne, Australia.Design/methodology/approachThe direction of this study commences with an introductory section on what it means to build green. This section is further brokendown to evaluate what factors are involved in constructing a green building. The work then shifts towards the green building from a sustainability point of view, touching base with the level of awareness that is surrounding the green building and the level of ignorance that goes with this. Furthermore, the research includes specific pointers which are strategically placed to directly grab the attention of those who lack knowledge in the area of green building by offering a brief, yet in-depth, discussion of possible materials that can be incorporated in the construction phase and will, in turn, create for a more efficient building. As such, life cycle energy is then introduced and calculations are carried out. These calculations offer a more logical form of validation to the previous points and issues raised, with the hope to achieve a more in-depth grasp of the process involved with green building.FindingsThrough comprehensive research, this paper has found the following outcomes. (1) A detailed insight into the contributing factors to green building in high-rise construction and the construction industry in general. (2) An increased understanding of the current status of green buildings within the construction industry. (3) The creation of an effective research methodology plan to implement throughout this research. The appropriate steps and measures, that were required to deliver a successful research piece, included all relevant information. (4) The level of involvement required when calculating the energy levels, including how to perform these calculations when given the correct data, and what these calculations mean concerning what they are defining.Originality/valueThe potential contribution that can be gained from this research is the awareness that is raised in the research and development of green buildings in high-rise construction. This can be achieved by the use of certain materials such as new energy-efficient building materials, recycled materials, etc. Through the incorporation of certain green building methods, an opportunity for cost savings becomes an incentive for the client and builder as the chance for a larger profit margin becomes readily available. In addition to these issues that are anticipated for the potential contribution through this research, the sustainability aspects are also expected to prevail as the construction industry is likely to evolve with changing standards and expectations due to the publicity high-rise buildings achieve, it is more than likely that this research discussion will be adopted willingly and positively promoted for all those involved within the construction industry to get involved. The intention remains that this research paper will be able to contribute a new way of thinking and a new approach to the way of building in the 21st century. As this would be the ideal outcome, the aim remains to portray and deliver information surrounding the views that remain for and against the implementation of green buildings in high-rise construction.

High performance, shape manipulatable transparent wood based on delignified wood framework and exchangeable dynamic covalent vitrimers

Transparent wood (TW) combining unique anisotropic structures with advantageous properties has many promising applications in advanced building fields. However, achieving shape manipulatable TW with high-performance remains a great challenge. Interestingly, vitrimers with dynamic covalent adaptable bonds presents a fascinating blueprint for prompting the advancement of multifunctional TW. Herein, a high-performance shape manipulatable TW with exchangeable dynamic thiocarbamate bonds (TCBs) was fabricated by the delignification and subsequent impregnation of stimuli-responsive vitrimers through solvent-free thiol-isocyanate click reaction by a low temperature solidification. The as-prepared TW exhibited impressive properties, for example, remarkable optical transparency (transverse transmittance of ≈90 % and haze of ≈90 %), attractive light management ability, low thermal conductivity (≈0.30 W·m−1·K−1), excellent mechanical properties (longitudinal tensile strength of 37.24 MPa and flexural strength of 48.88 MPa), and fascinating shape manipulation, which make our TW has promising potential applications as energy efficient and intelligent building materials. In addition, this feasible strategy provides a new avenue to design and combine multi-functional TW with high-performance to expand its applications in building construction.

Magnetically Doped Molybdenum Disulfide Layers for Enhanced Carbon Dioxide Capture.

Carbon capture and storage (CCS) technologies have the potential for reducing greenhouse gas emissions and creating clean energy solutions. One of the major aspects of the CCS technology is designing energy-efficient adsorbent materials for carbon dioxide capture. In this research, using a combination of first-principles theory, synthesis, and property measurements, we explore the CO2 gas adsorption capacity of MoS2 sheets via doping with iron, cobalt, and nickel. We show that substitutional dopants act as active sites for CO2 adsorption. The adsorption performance is determined to be dependent on the type of dopant species as well as its concentration. Nickel-doped MoS2 is found to be the best adsorbent for carbon capture with a relatively high gas adsorption capacity compared to pure MoS2 and iron- and cobalt-doped MoS2. Specifically, Brunauer-Emmett-Teller (BET) measurements show that 8 atom % Ni-MoS2 has the highest surface area (51 m2/g), indicating the highest CO2 uptake relative to the other concentrations and other dopants. Furthermore, we report that doping could lead to different magnetic solutions with changing electronic structures where narrow band gaps and the semimetallic tendency of the substrate are observed and can have an influence on the CO2 adsorption ability of MoS2. Our results provide a key strategy to the characteristic tendencies for designing highly active and optimized MoS2-based adsorbent materials utilizing the least volume of catalysts for CO2 capture and conversion.

Parametric studies on solidification of phase change material inside a cylindrical container toward achieving optimal energy efficiency

AbstractFifty percentage of the energy consumption inside any building is utilized for space cooling purposes. Energy storage through phase change material (PCM) is a viable option to fulfill the cooling energy requirements. The PCM is usually stored inside multiple containers/packets. However, the PCM's low thermal conductivity is a fundamental problem that delays the solidification time and can be accelerated through the nanoparticle addition and higher heat transfer fluid (HTF) flow rate. The recent advancement in nanoparticles opens an opportunity to enhance the heat transfer characteristics of the PCM. Therefore, a detailed parametric analysis is carried out for the PCM inside a cylindrical container to analyze the impact of thermal conductivity (“k”) enhancement through nanoparticle addition and the external surface heat transfer coefficient (“h”) on the solidification time reduction of the Water and RT21 PCM. It is concluded from the results that while utilizing gaseous HTF, it is better to increase the surface “h” rather than increasing the “k” of the PCM. On the other hand, for liquid HTF, “k” value played a significant role in solidification time reduction than increasing the “h” value. A considerate amount of solidification time reduction is possible through nanoenhanced RT21 and water PCM. This study will help the researchers/engineers design an energy efficient storage material toward achieving sustainability.

3D sustainable polysiloxane/ZnO hybrid membrane with enhanced reflectivity and flame retardancy for daytime radiative cooling

Polymer-based structural membranes have been considered as highly-efficient passive radiative cooling (PRC) materials but limited by the hazardous process and insufficient solar reflectivity during daytime. This work reported a sustainable phase-separation strategy for the fabrication of 3D porous polydimethylsiloxane/ZnO (3D PDMS/ZnO) hybrid membrane. The water was used as emulsifier of PDMS and as the evaporation of water drops in sealed environment, uniform cavities within 10 μm self-formed automatically, which were demonstrated to reflect more than 96% of solar radiations by cavities scattering. Meanwhile, the hybrid structure imparted the membrane with highly thermal emissivity surpassing 80% calculated from the transmittance. As the proof concept, the prepared film was used for outdoor daytime radiative cooling and presented excellent cooling performance, which could achieve about 7.5 °C of cooling effect even under the high solar radiation (∼906 W/m2). Moreover, the membrane showed excellent flame tolerance which satisfied the requirement for thermal safety of thermal-application materials. Therefore, the sustainably structural strategy and hybrid structure would propel the development of highly energy-efficient and thermal safe PRC materials.

Phase change materials incorporated into geopolymer concrete for enhancing energy efficiency and sustainability of buildings: A review

To reduce CO2 emissions by 55% by 2030, applying sustainable and energy-efficient materials like geopolymer concrete containing Phase change materials (PCMs) for infrastructure development is necessary. This study reviews the geopolymer mortar and concrete containing PCMs, including their characterizations such as workability, density, compressive strength, heat capacity, thermal conductivity, and their effect on energy consumption in buildings. Existing literature reveals that using geopolymers instead of OPC can reduce thermal conductivity and power consumption. The latent heat and melting temperature of investigated PCMs were in the range of 96.1–230 J/g and 21.9–33.8 °C, respectively. Although microencapsulated PCMs (MPCMs) such as E-EVA and St-DVB have slightly reduced the compressive strength of geopolymers, they still show a high strength compared to typical strength classes in normal concrete. Also, the workability of geopolymer concrete can remain in the acceptable ranges when the PCMs are incorporated in the low percentages. Furthermore, a considerable increase in the heat capacity is reported at the PCM’s melting temperature of geopolymer mortars and concretes, which can be deployed to conserve energy in the buildings.

Fabrication of Energy-Efficient Carbonate-Based Cementitious Material Using Sodium Meta-Aluminate Activated Limestone Powder

Fabrication of Energy-Efficient Carbonate-Based Cementitious Material Using Sodium Meta-Aluminate Activated Limestone Powder

Experimental investigation of thermal architected metamaterials for regulating transient heat transfer

Metamaterials have innovative functionalities as a result of artificial design. By arbitrarily designing thermal conductivity, thermal metamaterials have achieved thermal invisible cloaks, camouflages, and deceptions in steady-state. However, density and specific heat capacity have sometimes been overlooked, despite the fact that they are critical for managing transient heat flow and that density are an indicator of creating lightweight materials. The traditional materials are incapable of synchronously controlling thermal conductivity, density, and specific heat capacity. In this research, we experimentally investigate a novel thermal architected metamaterial that can modulate (accelerate or decelerate) transient heat transfer velocity without disrupting the steady-state. The novel type of thermal architected metamaterial achieves efficiency using a topology based on neutral inclusion theory. The transient heat transfer velocity is regulated by altering the effective density and specific heat capacity on the one hand, while the steady-state heat transfer is maintained by keeping the effective thermal conductivity on the other. The density of the architected metamaterial could be adjusted by selecting an appropriate specific heat capacity. The method we provide can be utilized to create lightweight energy-efficient materials (by accelerating transient heat transfer) as well as lightweight engineered thermal protection materials (by decelerating transient heat transfer). Moreover, the proposed thermal architected metamaterial could control heat flow velocity continuously, and this characteristic covers the gaps left by natural materials.

Benzaldehyde decorated octadecylamine for tailor-made molecular firefighting and efficient thermal energy management

• Benzaldehyde decorated octadecylamine for tailor-made thermal management. • Self-crosslinking of aromatic Schiff base for molecular firefighting. • Extensively reversible thermal transformation in a wide range of 30–100 °C. • Open a window for designing multifunctional phase change materials. More than 40% of the energy generated globally is consumed by residential and commercial buildings, so energy efficient materials for buildings are urgently needed at present. On-demand thermal energy storage/release using phase change materials (PCMs) can improve thermal energy utilization efficiency, however, they are facing low adaptability to temperature and easy flammability in the case of fulfilling high thermal management capacity. Herein, we report octadecylamine-based PCMs with tailor-made molecular firefighting and thermal energy management capability. These synthesized octadecylamine-based Schiff base-containing PCMs (SB-PCMs) may self-extinguish while encountering short-time fire and possess variable phase transition temperatures of 33, 42, 92, and 101 °C. Meanwhile, these SB-PCMs own high phase transition enthalpies of 161.4–183.4 J g −1 and excellent cyclic stability. When SB-PCMs as thermal energy management materials in wood plastic-based building materials, they show high adaptability to ambient temperature and excellent thermal management capability, achieving temperature regulation of 9.0 °C. Meanwhile, fire safety of the composite wood plastic materials is significantly improved. Detailed analysis confirms that the incorporated benzaldehyde with various positional substituted hydroxyl may induce noncovalent interactions (mainly hydrogen bond and π-π stacking) of SB-PCMs and further control their self-assembling processes, thus achieving multiple thermal responses of SB-PCMs; self-crosslinking charring of benzaldehyde-based Schiff base structure may retard fire spreading, therefore presenting molecular firefighting. Additional multistage thermochromic behaviors of SB-PCMs may extend their application in temperature-sensitive paint, intelligent fabric, etc. This work firstly represents a method for manipulating the multistage thermal and fire responses of PCM in the case of fulfilling high thermal energy management capacity and confirms its molecular-firefighting and energy efficient application in building materials.

Effects of various processing parameters on the mechanical properties and dimensional accuracies of Prosopis chilensis/PES composites produced by SLS

PurposeThe range of applications of the currently available biomass selective laser sintering (SLS) parts is limited and low-quality. This study aims to demonstrate the effects of the various processing parameters on the dimensional accuracy, bending strength, tensile strength, density and impact strength of the Prosopis chilensis/polyethersulfone (PES) composites (PCPCs) that were produced by SLS. The various processing parameters are laser power, scan speed, preheating temperature, scan spacing and layer thickness. In addition, the authors’ studied the effects of PCP particle size on the mechanical properties of the PCPCs.Design/methodology/approachThe PCPC specimens were printed using an AFS SLS machine (additive manufacturing). The bending, tensile and impact strengths of the specimens were measured using a universal tensile tester. The dimensional accuracy of the bending specimens was determined by a Vernier caliper. The formability of the PCPC at various mixing ratios of the raw materials was earlier investigated by single-layer sintering experiments (Idriss et al., 2020b). The microstructure and particle distribution of the various PCPC specimens were analyzed by scanning electron microscopy (SEM).FindingsThe mechanical strengths (bending, tensile and impact strengths and density) and the dimensional accuracy of the PCPC SLS parts were directly and inversely proportional, respectively, to the laser power and preheating temperature. Furthermore, the mechanical strengths and dimensional accuracy of the PCPC SLS parts were inversely and directly proportional, respectively, to the scanning speed, scan spacing and layer thickness.Practical implicationsPCPC is an inexpensive, energy-efficient material that can address the drawbacks of the existing SLS parts. It is also eco-friendly because it lowers the pollution and CO2 emissions that are associated with waste disposal and SLS, respectively. The optimization of the processing parameters of SLS in this study produced high-quality PCPC parts with high mechanical strengths and dimensional accuracy that could be used for the manufacture of the roof and wooden floors, construction components and furniture manufacturing.Originality/valueTo the best of the authors’ knowledge, this study is among the first to elucidate the impact of the various SLS processing parameters on the mechanical properties and dimensional accuracy of the sintered parts. Furthermore, novel PCPC parts were produced in this study by SLS.

Energetic Materials Based on N-substituted 4(5)-nitro-1,2,3-triazoles.

The regularities and synthetic potentialities of the alkylation of 4(5)-nitro-1,2,3-triazole in basic media were explored, and new energetic ionic and nitrotriazole-based coordination compounds were synthesized in this study. The reaction had a general nature and ended with the formation of N1-, N2-, and N3-alkylation products, regardless of the conditions and reagent nature (alkyl- or aryl halides, alkyl nitrates, dialkyl sulfates). This reaction offers broad opportunities for expanding the variability of substituents on the nitrotriazole ring in the series of primary and secondary aliphatic, alicyclic, and aromatic substituents, which is undoubtedly crucial for solving the problems related to both high-energy materials development and medicinal chemistry when searching for new efficient bioactive compounds. An efficient methodology for the separation of regioisomeric N-alkyl(aryl)nitrotriazoles has been devised and relies on the difference in their basicity and reactivity during quaternization and complexation reactions. Based on the inaccessible N3-substitution products that exhibit a combination of properties of practical importance, a series of energy-rich ionic systems and coordination compounds were synthesized that are gaining ever-increasing interest for the chemistry of energy-efficient materials, coordination chemistry, and chemistry of ionic liquids.

Mixed polyamines promotes CO2 adsorption from air

The deployment of large-scale direct air capture (DAC) technology relies on the development of energy-efficient and cost-effective CO2 capture materials. The high desorption temperature of the current DAC adsorbents, especially the supported polyamines, is undesirable. In this work, the "mixed-polyamines" concept was adopted to prepare class 1 adsorbents by impregnating both tetraethylenepentamine (TEPA) and diethanolamine (DEA) into the mesoporous SBA-15. The synergy of TEPA and DEA influences the reaction mechanism between CO2 and amines sites, resulting in higher amine efficiency and lower regeneration temperature. Moreover, CO2 adsorption and desorption kinetics are enhanced by the introduction of hydroxyl groups from DEA. The desorption process of solid polyamines-loaded adsorbents fits well with the Avrami model under ultra-dilute CO2 concentrations. SBA-15 loaded mixed polyamine with a weight ratio of TEPA to DEA equaling to 4 shows a maximum CO2 adsorption amount of 1.93 mmol/g at 400 ppm CO2 and 25 °C, a fast adsorption rate of 1.82 mmol/(g·h), and a desorption rate of 0.26 mmol/(g·min) at 80 °C within the first 5 min, which is believed to be a promising DAC adsorbent for practical application.

ИСПОЛЬЗОВАНИЕ НАНОТЕХНОЛОГИЙ ДЛЯ ПРОЕКТИРОВАНИЯ СТРОИТЕЛЬНЫХ КОНСТРУКЦИЙ

Russia has a developed industry of building materials, which today implements an energy- and resource-saving model of its development. The implementation of the state policy of resource conservation is carried out in two main directions: the first direction is to save resources in the production of materials, the second is to increase the production of energy–efficient materials that allow saving energy carriers during their operation. Modern construc-tion in Russia is guided by European construction standards, which, in turn, provides for the construction of ener-gy-saving buildings with minimal energy consumption from external sources. This is ensured by the use of struc-tural and thermal insulation materials in the construction of external walls. In modern structural and thermal insu-lation materials for energy-saving construction, high requirements are imposed on their thermal properties, me-chanical strength and comfort level. From the point of view of simultaneous satisfaction of these requirements, ceramic materials have obvious advantages over other materials, in particular cellular concretes, which, with al-most the same level of thermal conductivity, are characterized by the least hygroscopicity and significantly greater strength. An objective prospect for the development of structural and thermal insulation ceramics is the production of hollow ceramic stones with increased thermal efficiency for their use in economical single-layer external wall structures without additional insulation. The products of individual Ukrainian manufacturers and even imported analogues of the most famous European manufacturer (Wiernerberger Company, Austria), when used in single-layer walls, do not provide regulatory requirements for the heat transfer resistance of masonry for the first temper-ature zone of Russia, which occupies the majority of the territory (60%). This requires the improvement of domes-tic products in the direction of improving their thermal characteristics (reducing thermal conductivity and increas-ing thermal resistance).

Prospects of Robot Laser Cutting in the Era of Industry 4.0

Laser cutting is a non-contact thermal cutting process and an integral part of manufacturing. In metal processing, laser cutting is at the forefront of the manufacturing chain followed by joining and manufacturing processes like welding. The future of metal manufacturing processes like laser cutting shall rely on intelligent systems such as automation and robotics based on the advancement of technology and digital transformation spearheaded by Industry 4.0. Moreover, the digital transition where robots and automated systems are key drivers creates a broader platform to utilize energy-efficiency materials. Such energy-efficient materials include high-strength steels (HSS) for structural applications (e.g. bio-energy structures, wind turbines, ice-going vessels) onshore, offshore and in the Arctic region. The aim of this paper is to elucidate the prospects of robot laser cutting systems in the framework of integrated metal manufacturing in future factories. Previous studies on laser cutting technologies are examined based on scientific and industrial perspectives. Robot laser cutting system is compared with the well-known flat-bed laser cutting CNC machine in several aspects including flexibility in manufacturing, ease for digitalization, off-line capabilities and investment analysis. The findings shall help to determine the competitiveness of robot laser cutting systems with flat-bed laser cutting CNC machines, especially when considering metal manufacturing in small and medium-sized enterprises (SMEs). The outcome of this study is to stir up experimental and computational research on robot laser cutting systems of metals, and help companies in their decision-making process when deciding which laser cutting system will best suit their manufacturing operations in the future.

An Assessment of Green Rural Road Criteria and Elements for My Green Rural Road Index: A Case Study in Pengerang, Johor

The rural road networks were built to connect the rural people to the town area or to other destination required by the local residents. Normally the rural roads will be developed to connect or increase the socio-economic opportunity in rural area. The green road is one of the key areas that can be look into to create the sustainable concept based on three key aspects namely social, environmental and economic factors. The main focus of the economy aspect is to increase the profits using more efficient resources, especially materials, improving the quality of life by meeting the national needs of social aspects and protecting the environment from the effects of CO2 emissions and efficient use of natural resources for environmental aspects. Therefore, it is important that stakeholders include sustainability criteria in their projects. The application of a sustainable concept on the road can be assessed by the green road evaluation tool. Therefore, the main aim of this study is to build tools to evaluate and declare green rural roads in Malaysia. The data for this study were gathered through group discussions with road construction experts and distributed questionnaires to identify sustainability factors. Then the data were analysed by factor analysis method using SPSS software. Based on the result, there are five main sustainable criteria: Sustainable Design and Construction, Social and Safety, Energy Efficiency, Environmental and Water Management and Materials and Technology that are included in the development of the green road qualification system. The analysis indicates that the social and safety become the prime criteria among other criteria.

Review of thermal performance, hygrothermal behavior, and carbon sequestration in hemp concrete in order to make it an energy-efficient and eco-friendly material

Review of thermal performance, hygrothermal behavior, and carbon sequestration in hemp concrete in order to make it an energy-efficient and eco-friendly material

Performance of Mechanized Pugged Soil Stabilized Adobe

The soil has been the most abundantly available construction material for use in human society, and it has been considered the primary material for any form of construction. Local availability and ease of handling make it one of the most energy-efficient, cost-effective, and reliable building materials for any structure. The traditional construction technology using soil has been undergoing a considerable change over a while, enhancing its quality and durability as a construction material. It has immense benefits in minimizing the impact of environmental pollution. The paper mainly focuses on comparing the strength of Soil Stabilized Adobe (SSA) (size −230 mm*108 mm*100 mm) prepared by mechanized pugging (using wet mixer grinder) and manual pugging. Compare to manual pugging, the process of mechanized pugging increases the consistency of the soil structure making it a homogenous mixture of clay, silt, sand and stabilizers. The soil considered in the study was red soil containing kaolinite type clay and has been reconstituted for 10% clay by adding M−sand. The different parameters considered in the study were: variation in pugging time (Mechanized Pugging −3min, 6 min, and 9 min and Manual Pugging −10 min and 15 min) and stabilizers (Cement alone (8%), lime alone(8%), and Combination of cement (6%) + lime (3%)). The following tests were conducted on SSA samples to study their performance: dry density, compressive strengths, water absorption and initial rate of absorption. The findings showed that, the SSA made by Mechanized pugging is more advantageous compared to Manual Pugging, as it saves time of pugging, increases the strength and consistency of the soil and reduces water absorption. Additionally, increase in pugging time improves the SSAs quality.

Technological aspects of the preparation of polymer composites of building materials and coatings

In accordance with the principles of sustainable development, improving the quality and durability of structural elements and coatings, the construction industry requires the development and the implementation of resource- and energy-efficient building materials, as well as innovative technologies for their production. The use of complex modifiers for no-slump concrete mixtures and concrete is becoming increasingly widespread in modern materials science. The article presents the studies of influence of polymer additive structured carbon nanomaterials on physical and mechanical characteristics of no-slump concrete mixtures. The methods of infrared spectroscopy and thermogravimetric analysis showed that the use of carbon nanomaterials alters the structure of no-slump concrete mixtures significantly. As a result of the fact that the high-strength nanomaterial is the centre of crystallization of cement stone neo-formation, a denser reinforced microstructure is formed, which increases significantly the strength properties of no-slump concrete mixtures. The inclusion of a complex polymer additive in no-slump concrete mixtures leads to higher and longer plasticizing, which plays an important role in the production of monolithic products. It was determined that, in the presence of a complex modifier (a polymer additive structured by carbon nanotubes), the crystalline structure of calcium silicate hydrate is compacted, which determines high physical and mechanical characteristics of modified no-slump concrete mixtures. It was experimentally shown that the additive acted as an accelerator of a setting and hardening cement test and also increases its strength characteristics. In general, in this study, there is a water-reducing effect from the application of the additive for all no-slump concrete mixtures. Water consumption is reduced by 5% of the mass, while the strength is increased by 19%. No-slump concrete mixtures recipes modified by polymer additives, structured by carbon nanotubes, with high performance were developed.

Optical Behaviour of Caffeine Mixed Perovskite Photoanode for Photovoltaic Application

Halide perovskites such as methylammonium lead triiodide (CH3NH3PbI3) are attracting attention as energy-efficient light absorber materials for photovoltaic applications owing to their solution processing-power, tunable bandgap, strong absorption coefficients and cost effectiveness. Scanning Electron Microscope (SEM) and Ultra-Violet Visible Spectroscopy (UV-vis) were used to characterize the prepared samples. The substrates were rinsed with propanol to remove impurities and later sintered before precursor deposition with different caffeine ratios via spray pyrolysis. The deposition method was used due to its homogenous ability. The SEM results indicate that the introduction of caffeine enhances nucleation, leading to an increase in the growth rate compared to the control. The UV-vis result shows a redshift to a higher wavelength, indicating an increase in visible light absorption which is attributed to the spectral overlap between the CH3NH3PbI3 absorber and caffeine. The bandgap (Eg) energy analysis further confirmed that the caffeine-modified photoanode is a potential light absorber in perovskite solar cell applications. This study provides a good understanding of the optical behaviour of caffeine-mixed perovskite photoanode nanostructures and a promising approach for photon energy management.