Mineral Wool Research Articles

The influence of CO2 concentration on production processes in digital artificial agricultural ecosystems

It is noted that digital artificial agricultural ecosystems imply the use of digital control systems of abiotic factors, with appropriate software and algorithms. The algorithm through thermoregulation ensures the highest flow of moisture and nutrients through the plant. The leaf temperature corresponds to the maximum rate of photosynthesis. It is shown that CO2 assimilation and thermoregulation are related, as water vapor and carbon dioxide pass through the same stomatal openings. The aim of the research is to establish, for selected samples of vegetable crops, the level of CO2 concentrations at which the biomass growth of these crops is maximal, as well as the degree of thermoregulation heat reduction for average CO2 concentrations of 1000 ppm and higher. A specially designed stand was used for the studies. The following crops were used for studies of the influence of CO2 concentration on the thermoregulation heat: from vegetables the cucumber cultivar “Courage” and from green spices the cultivar “Coriander”, and for studies of the influence of CO2 concentration on productivity - salad cultivar “Gambrel”. The samples were planted in four cubes of mineral wool, in each of which five plants were placed. Variable concentration was provided by a system of carbon dioxide supply from a cylinder with a reducer, a hose and an electromagnetic valve. It was experimentally proven that the increasing of the CO2 concentration leads to an increase in the weight of green mass, and this increase has an extreme at the concentration of 2944 ppm (for the lettuce culture), with a slight decrease in thermoregulation temperature (for cucumber by 1.4 °C, and for coriander by 0.47 °C). Such a decrease will not lead to a significant deterioration of thermoregulation processes and may not be taken into account in the operation of digital control of them.

Thermal insulation of engineering structures with mineral wool based on basalt fiber

The most vulnerable link of central heating systems are heat pipelines. Steam and condensate pipelines devoid of thermal insulation are a constant source of heat loss, which can be easily eliminated. In most cases, the thermal insulation of all heated surfaces does not present significant difficulties. There may be situations when the insulation was removed during maintenance or repair and not restored at the end of the work. Removable thermal insulation elements of valves and other devices may also be missing. To ensure the economic efficiency and reliability of heat supply, it is necessary to intensively modernize heating networks. The most effective way to increase the energy efficiency of engineering structures is the use of modern structural solutions using thermal insulation materials. In addition, it allows you to reduce operating costs, that is, to achieve significant savings in fuel resources. The economical efficiency of district heating systems at the current scale of heat consumption largely depends on the thermal insulation of equipment and pipelines. The struggle to reduce transport heat losses in pipelines is the most important means of saving fuel resources. The paper considers the possibility of improving the energy efficiency of engineering structures through the use of modern structural solutions using thermal insulation materials based on basalt fiber.

THERMAL BALANCE OF A HOUSE WITH AIR SOLAR COLLECTOR AND HEAT STORAGE FOR THE CONDITIONS OF THE BAIKAL NATURAL TERRITORY

In this work, thermal engineering calculations of the energy efficiency of a low-rise house made of timber, insulated with mineral wool for the conditions on Lake Baikal, were carried out. As a prototype for determining the thermal characteristics, an information model of a building typical of the island in terms of architecture and size was developed using BIM technology. The engineering equipment additionally includes an air solar collector and a heat storage device in the form of a heat-insulated soil massif. Two variants of operation are considered. In the first case, the house is operated as housing for five people, and in the second case as a hotel for ten people. The analysis of energy costs for heating for individual months and for the year as a whole was carried out. The heat consumption for heating the ventilation air and its share in the total heat costs in the mode of a residential building and a hotel are determined. The possibility of a significant reduction in energy consumption when using the heat recovery of ventilation air is shown. An additional reduction in energy consumption from traditional heating systems through the use of an air solar collector is considered. It is shown that the accumulation of excess heat by a special thermally insulated array of soil under the house leads to the stabilization of the thermal regime. The specific characteristic of heat consumption by the house is determined.

Study on Energy Efficiency Using Building Information Modelling (BIM) at Shared Library Pagoh Higher Education Hub

Structures in Malaysia, particularly commercial buildings, have been exceeding the benchmark of building energy usage over the past few years. By maintaining thermal comfort of building under hot climate in Malaysia, air-conditioning system became a basic demand which incessantly operating to fulfil comfort requirement for the occupants in the library. Regards to this, research on energy efficiency using Building Information Modelling (BIM) software by simulating energy analysis was carried out in order to increase energy efficiency of the library. Mineral wool and Polyurethane Foam (P.U.F.) are the materials which proposed to apply in existing wall of building as the thermal insulation layer to increase thermal resistance when external heat transfer through the walls. The Objective of the study is to determine the existing building energy consumption and compare with energy analysis of mineral wool and polyurethane foam. The findings of the building energy analysis simulated by Green Building Studio (GBS) are then compared to discover the most appropriate walls for reducing the building’s energy consumption. P.U.F with its characteristics of high R-value and low U-value, obtain the most effective energy analysis which provide benefits of lowering total annual energy consumption of 294,651 , total annual energy cost of RM 107,645, and energy use intensity (EUI) of 121.7.

The role of magnesium ions for the growth and development of tomatoes when growing in protected soil conditions

Tomato is one of the main and popular vegetable crops not only in Ukraine, but throughout the world. According to the Food and Agricultural Organization (FAO), tomatoes occupy the first place in the world in terms of cultivated areas among all vegetables — more than 4 million hectares. In Ukraine, about 93,000 hectares — about 24% of the total area under vegetables — are devoted to this culture. With the advent of high-intensity technologies with the use of drip irrigation systems, tomato yields of 120–140 t/ha in open ground, and more than 50 kg/m2 in sheltered ground, became real. Nowadays, the method of small-volume hydroponics with the use of drip irrigation is becoming more and more widespread in greenhouse farms. As a substrate, special materials are used — mineral wool, coconut, peat, etc. The selected substrate functions as a medium for the roots, feeding is carried out by supplying a fertilizer solution. When growing on a substrate, it is necessary to dose fertilizers very accurately and provide plants with a sufficient amount of nutrients. The paper investigates the effect of the concentration of the macroelement magnesium in the mineral wool substrate on the growth and development of the Campari (cocktail) tomato culture in protected soil conditions. It was established that the photoelectrocolorimetric method for determining the magnesium content in mineral wool hoods is quite sensitive, simple, and recommended for use in serial analyses. The determined content of magnesium salts (72.0 mg/l) turned out to be insufficient for growing tomatoes in the period of mass fruiting. Controlling the magnesium content allows you to significantly prevent tomato chlorosis and obtain high-quality crops.

The influence on portal frame buckling of different cladding systems — A comparative numerical study considering stressed skin effect

The purpose of the current paper is to compare and to estimate in a numerical manner the influence of the cladding type on the sway stability indicators of the structure, such as buckling modes and critical load multiplication factors αcr. The paper presents comparative results obtained in terms of stabilization effects given by trapezoidal sheeting and mineral wool core sandwich panels supported by Z purlins applied on the reference cold-formed steel structure. A parametric study was also performed, showing the degradation tendency of stressed skin effect, as the length is increased by adding additional bays to the structure.

Study on seismic performance of suspended ceiling system with semi-free boundary condition

The failure of suspended ceiling system (SCS) has been one of the most widely reported seismic damage to non-structural components in buildings in recent years. In China, there are several types of SCSs applied in practice, among which the double-layer SCS with mineral wool boards is widely used in public buildings. It was found from the past earthquakes that the ceiling perimeter is one of the most vulnerable parts of SCS due to lack of reliable connection at the boundary. In this study a new semi-free boundary condition is proposed to improve the seismic performance of SCS. The full-scale shaking table tests on this type of SCS installed on a steel platform are conducted. The working mechanism, failure patterns, damage evolution, and earthquake responses including acceleration, displacement, and strain responses are studied. Experimental results verify that the proposed boundary condition is able to protect the ceiling perimeter from damage. The failure of SCS is mainly caused by the high vulnerability of grid connections. The pounding at the perimeter of SCS affects the seismic performance of the SCS harmfully. Effective seismic measures should be developed to reduce the impact between the ceiling and surroundings. A simplified numerical model for SCS with semi-free boundary condition is developed using OpenSEES. The calculated acceleration and displacement responses agree well with the test results. Moreover, seismic design recommendations for the type of SCS are provided.

Simulation and experimental investigation on one-step process for recovery of valuable metals and preparation of clean mineral wool from red mud

Red mud (RM) is a hazardous alumina industrial solid waste and its utilization faces three major challenges, namely, efficient recovery of valuable metals, favorable control of hazardous substances, and complete utilization of residues. We simultaneously achieved the three goals in a short one-step process, which was inspired by green chemistry principles and focused on multi-objective coupled control. Iron-based metal elements were recovered in reduction smelting process to produce pig iron. Molten slags after smelting were rapidly cooled and fiberized to produce mineral wool and hazardous alkaline substances were immobilized in vitreous fibers. The smelting-reduction process, fibration capacity of RM-based molten slags, and performance and environmental impact of prepared mineral wool were investigated using thermodynamic, molecular dynamics simulations, and experimental methods. The results indicated the recovery rate of Fe could reach above 87%. The obtained mineral wool showed satisfactory properties with the fibrosis rate of around 73%–92%, the mean fiber diameter of 1.57–5.62 μm, and the mean fiber tensile strength of 1520–6700 MPa. The highest Na+ leaching concentration was under 1.42 mg/L and the solidification rate of Na+ in different samples was above 99.8%. This paper provided a fresh approach to achieve clean and high value-added utilization of RM.

Thermal insulating walls based on Ti3C2TX as energy storage panels for future smart house

Sustainable decentralized energy generation and storage in the cities are critical for a sustainable future. Here we design a smart energy storage device based on thermal insulation and MXene (Ti3C2Tx) for powered future smart homes. The modified surface of a common thermal insulation wall (TIW) using Ti3C2Tx and polyaniline (PANI) by in situ chemical oxidative polymerization of aniline monomer serves as an energy storage device in the wall and, at the same time, maintains the temperature inside the house. The as-fabricated PANI@Ti3C2Tx-TIW-based supercapacitor exhibited high specific capacitance with outstanding rate capability, cyclic stability, mechanical stability, and power density, and functions in extreme temperatures (−15 °C to 45 °C). Further, the device was integrated into real rock mineral wool insulation to develop a future house energy storage system that can store electricity in the house wall and supply power to operate emergency evacuation and alert devices in the event of a disaster.

The Investigation on Mineral Wool Performance as a Potential Filter to Remove TSS in Cikapayang River, East Jawa, Indonesia

Mineral wool has been used as a filter medium that reaches approximately 95% removal efficiency of total suspended solids (TSS) on a laboratory scale. However, there is no research available has been applied on a larger scale. Hence, this study investigated the ability of mineral wool to remove TSS in two separate segments of the Cikapayang River at different seasons. This analysis utilizes a mineral wool type I, with a dimension of 180×30×120 cm placed in segment 2, and a mineral wool type II with a dimension of 325×30×100 cm placed in segment 9. Samples were taken using the grab sampling method to analyze the TSS concentration before and after being filtered by mineral wool. This investigation concluded that mineral wool could reduce the TSS concentration by up to 65%, and the removal capacity increased by about 6.82% during the dry season. The concentration of TSS in the dry season positively correlates with the increase in the removal capacity of the media. Mineral wool of type I in segment 2 had a better removal ability (31.43%) than type II in segment 9 (14.71%). This research shows that mineral wool can be used as a support material in sanitation sites in large cities experiencing quality degradation in their water bodies.

Impact of the Soundproofing in the Cavity of the Synthetic Jet Actuator on the Generated Noise

The synthetic jet actuator (SJA) generated high noise which limits the area of its application. In this paper, the five actuators with different types of soundproofing in the cavity were tested and compared to the classic actuator. The resistance and the sound pressure level (SPL) were measured for real power P=1, 2, 4 W, and frequency in a range of 20–150 Hz. The resonant frequency of actuators was designed. Only one type of soundproofing had a significant impact on the resonant frequency. The use of soundproofing in the actuator cavity increased or did not affect the generated noise at a frequency below 120 Hz and only the mineral wool significantly decreased the noise at a frequency above 120 Hz– even 7 dBA. The direction for further investigations was set.

Alkali-Activated Binder Based on Cupola Dust of Mineral Wool Production with Mechanical Activation

The development of low-carbon alkali-activated binders based on production waste is one of the most sought-after areas of development of building materials science. The article examines the results of studies of the structures of cupola dust and the assessment of its ability to hydrate when exposed to alkaline activation. Technological preparation of dust by sifting it through a 0.16 mm sieve and subsequent mechanical activation for 120 s to a specific surface area of 733 m2/kg is proposed. The best results were shown by the composition of cupola dust with an alkaline activator of 50 wt.% 8.3 M NaOH and 50 wt.% Na2SiO3. After 28 days of natural hardening for this composition, the bending strength was 12.7 MPa and the compressive strength was 68.3 MPa. The analysis of the influence of hardening conditions showed that the temperature–humidity treatment of concrete at a temperature of 90 °C for 12 h accelerates the process of curing to 80–90% of natural conditions. The porosity of the samples after heating was established, which is 24–25%. The mineralogical composition of the products of the cement matrix structure’s formation, which is represented by minerals of the zeolite group, was specified.

An experimental study on a cylindrical-conical cavity receiver for the parabolic dish collector.

Solar thermal energy is a promising solution to the environmental and energy demands issues which the world is faced with them. Among all the solar thermal collectors and solar towers used in this field, parabolic dish collectors are one of the preferable options for researchers due to their high working temperature range and high thermal performance. It has been proved that cavity receivers in solar dish collectors are the best way to achieve the best thermal performance. The main concern in the cavity receivers is their thermal efficiency enhancement by employing different geometries. The hybrid geometry of cylindrical-conical can be used to achieve the high pressure drop and low thermal efficiency of conventional cylindrical and conical cavity receivers, respectively. Furthermore, using proper insulation for the cavity receiver helps to performance enhancement of the dish collector. Ceramic fiber insulation can be suitable for this purpose due to its good thermal properties and fewer environmental issues. Hence, in this study, the objective of efficiency enhancement of parabolic dish collector is followed by utilizing a cylindrical-conical cavity receiver equipped with the fiber ceramic insulation. The results show that ceramic fiber is better insulation than the common mineral wool insulation and can enhance thermal performance by 5.03% on average. In addition, the maximum, average, and minimum thermal efficiencies of the cylindrical-conical cavity receiver by using the ceramic fiber insulation and water as the working fluid were obtained up to 38.77%, 35.19%, and 32.66%, respectively.

Mechanical and Fire Performance of Innovative Hollow Glue-Laminated Timber Beams.

Fire safety greatly contributes to feeling safe, and it is a key parameter for the selection of building materials. The combustibility of timber is one of the main reasons to have the strict restriction on timber for use as a building material, especially for multistory buildings. Therefore, the main prerequisite for the use of timber in buildings is to ensure adequate fire resistance, using passive and active fire protection measures. This article contains the results of mechanical and fire experimental tests of both normal and innovative hollow glued laminated timber beams. A total of 10 timber beams were tested at ambient temperature, and 3 timber beams in fire conditions, which differed in cross-section type but also in the applied fire protection. The first beam was a normal GL beam without fire protection, the second a hollow beam covered by intumescent paint, while the third was also hollow, additionally protected by mineral wool infill inside the holes. The load-carrying capacity of the hollow beam in ambient conditions was estimated at 65% of the load-carrying capacity of a normal GL beam. Fire tests indicated that hollow timber beams with both intumescent paint and mineral wool infill failed at a similar time as a normal GL beam without fire protection. One-dimensional β0 and notional charring rates βn were obtained. Time to the protective material failure was 17 min. The main cause of failure of hollow beams was the appearance of delamination due to the reduction of the lamella bonding surface.

Hygrothermal performance of highly insulated external walls subjected to indoor air exfiltration

The study comprises three laboratory tests in which typical Finnish highly insulated (HI) walls were exposed to concentrated leakages of indoor air under steady outdoor temperatures of 1–5°C. Airflows with a relative humidity of 50% and at rates of 1–3 L/min were directed close to the wooden frames inside the walls. The thermal resistance ratios between the exterior sheathing(s) and the whole wall (Γ) were 20%–22% and 1%–10% for the HI and baseline (BL) walls. The HI walls that presented Γ values of at least 20% were observed to be resistant to air exfiltration, and their durability was not affected by the addition of a gypsum sheathing outside the wooden frame or a more permeable vapor retarder. This is related to the negative linear correlation that exists between the moisture accumulation rate in wood-based material and the dew point depression (DPD) value. The developed approach, called the DPD method, shows that a significant degree of moisture accumulation does not occur even for DPD values of as low as −2°C if the exterior sheathing is vapor permeable. The airflow does not penetrate into the rigid mineral wool sheathing, which helps to avoid interstitial condensation. Regardless of thermal transmittance, the HI and BL walls with maximum Γ values of 1% were exposed to a high relative humidity and even interstitial condensation because the DPD values were often below −2°C. For these walls, the mold index analysis and visual observations confirmed the local risk for mold growth on the opposite side of the leakage point. In practice, long-term mold growth may be limited if the seasonal periods during which the outdoor temperature is 1–5°C last for a maximum of about 1 month every year.

Minimizing the Global Warming Potential with Geopolymer-Based Insulation Material with Miscanthus Fiber.

Approximately 45% of global greenhouse gas emissions are caused by the construction and use of buildings. Thermal insulation of buildings in the current context of climate change is a well-known strategy to improve the energy efficiency of buildings. The development of renewable insulation material can overcome the drawbacks of widely used insulation systems based on polystyrene or mineral wool. This study analyzes the sustainability and thermal conductivity of new insulation materials made of Miscanthus x giganteus fibers, foaming agents, and alkali-activated fly ash binder. Life cycle assessments (LCA) are necessary to perform benchmarking of environmental impacts of new formulations of geopolymer-based insulation materials. The global warming potential (GWP) of the product is primarily determined by the main binder component sodium silicate. Sodium silicate’s CO2 emissions depend on local production, transportation, and energy consumption. The results, which have been published during recent years, vary in a wide range from 0.3 kg to 3.3 kg CO2-eq. kg−1. The overall GWP of the insulation system based on Miscanthus fibers, with properties according to current thermal insulation regulations, reaches up to 95% savings of CO2 emissions compared to conventional systems. Carbon neutrality can be achieved through formulations containing raw materials with carbon dioxide emissions and renewable materials with negative GWP, thus balancing CO2 emissions.

Eco-efficient transformation of mineral wool wastes into lightweight aggregates at low firing temperature and associated environmental assessment

Waste recycling is one of the key elements to mitigate the environmental problems that threaten our society. Mineral wool is currently the most widely used insulation material in the European Union, so the amount of waste generated in the demolition and restoration of buildings has increased alarmingly. This work investigates for the first time the use of glass wool (GW) and rock wool (RW) as a component in the manufacture of lightweight aggregates, showing that both can be suitable raw materials considering the density (1.3–1.5 g/cm3) and mechanical strength (2–6 MPa) obtained. In addition, the use of GW would help to reduce the firing temperature significantly (700 °C) compared to that normally used in the manufacture of these materials (around 1200 °C), which would imply significant energy savings. Considering that thermal insulation materials and lightweight aggregates are among the most widely used materials in the construction sector, the work presented here also evaluates the environmental impact associated with the manufacture of lightweight aggregates with RW and GW in comparison with the traditional process, using the Life Cycle Assessment (LCA) methodology. A significant environmental improvement has been observed in almost all the analyzed impact categories of the artificial aggregates manufactured with mineral wool with respect to traditional LWAs.

Development of the project of modular prefabricated buildings

The issues of working design with the construction of modular prefabricated buildings, with the minimization of cold bridges are revealed. Cold bridges are typical for prefabricated buildings with inadequate attention to the design of both load-bearing metal and enclosing structures, as well as their connections. Connections should not pass through its cross section both zero and negative temperatures. As a result, an original project of two modular buildings was developed from easily prefabricated metal structures and wall structures with light mineral wool filling. This project is also intended for sharply continental regional natural and climatic conditions (regardless of the geographical location on the territory of Kazakhstan – south-eastern Kazakhstan, central, eastern or western Kazakhstan. In winter, natural and climatic conditions are similar in these areas). As a result of this study, it was found that the developed project meets the requirements of thermal insulation – at the interface of the supporting and enclosing structures. The thermal insulation requirements of the above structures are important to eliminate the dew point and consequently the formation of moisture and mold in all structures. In turn, mold and other microorganisms, as studies show, adversely affect the health and normal stay of people in the premises, both during the night and during the day. Many developers do not consider these factors in prefabricated buildings. These buildings are intended for various industries. For example, in healthcare, these are mobile hospitals. In military camps – buildings of temporary residence as barracks, etc.

Performance evaluation of lightweight insulating plaster for enhancing the fire endurance of high strength structural concrete

Structural concrete is a widely used building material due to its versatile characteristics including higher compressive strength and longevity. However, when exposed to fire, concrete experiences faster degradation in its mechanical properties and is also susceptible to spalling. To overcome this problem, the possibility of lightweight plaster application on High Strength Concrete (HSC) is explored in the presented investigation. Insulation plasters, namely Sand Plaster (SP), Gypsum Perlite Plaster (GPP), and Gypsum Mineral Wool Plaster (GMP) were developed. This investigation evaluates the compressive strength, bond strength, and shear strength of concrete which is exposed to the standard fire temperature. Varying cooling conditions which involved air and water were adopted to cool the concrete specimens after the elevated temperature test. Further, the damaged concrete and the plaster were examined to analyse the physical changes. Analysis of the study reveals that more number of denser surface cracks and higher mass loss was observed for reference and SP specimens. Temperature penetration at the core of cube, bond, and shear specimens is less for the GPP and GMP specimens when compared with the SP specimens. At higher temperatures (986 °C), the reference and SP specimens show a lower bond and shear strength with higher slip values. Specimens insulated with GPP and GMP exhibited a low-temperature penetration at the core portion. Also, the results of the study reported the higher residual compressive, bond, and shear strength compared to other specimens.

Разработка методики испытаний заделки технологических отверстий на этапе эксплуатации в целях обеспечения безопасности на строительной площадке

Safety of the personnel at the construction site from falling from a height depends on the control of risks and the minimization of work at height, as well as on the compliance with the occupational safety rules. The article touches upon the topic of studying one of the solutions for sealing process holes when laying engineering communications at a construction site. The purpose of the study is to provide comprehensive and individual protection against falls from a height. The tasks that were solved during the study: development of a methodology with dynamic and static load on the seam during operation; checking the residual strength; development of criteria for operability and safe use; analysis of the results obtained with the recommendations for use. The tests consist in modeling the operating mode of the mounted seam between the facade of the building and the floor slab for the impact of static and dynamic loads before the appearance of deformations. Previously, the seam with a width of 200 mm is filled with layers: mineral wool, fire sealant, concrete screed with metal mesh reinforcement. The load is transmitted through the installation, which stimulates the fall of an object or the impact of a person foot with a load, the bearing capacity of the sandwich is checked. The data obtained are analyzed and correlated with the criteria of the operability and safe use. Results of the study: a methodology was developed that can be used for testing various structural solutions to seal the seam; the proposed method allows to determine bearing capacity of the structure and to check the minimum destructive load. The presented design of filling process holes reduces the risk when the user may fall into a sealed process hole during operation and increases the overall safety factor at the construction site.