Papers by Keyword: Additive

Abstract: For concrete constructions built as underground spaces, basements or cellars, it is necessary for these constructions to be able to resist the influence of groundwater pressure that could disrupt the compactness of the entire construction by its action. For this reason, constructions of so-called white boxes are often used. White boxes are concrete constructions whose main capability is high water impermeability, exhibiting at the same time minimal volume changes. These properties could be accomplished by a series of several technological precautions, one of which is the composition of the concrete mixture itself. The aim of this paper is to evaluate the influence of finely ground limestone and the latent hydraulic addition of finely ground blast furnace slag on the properties of concrete composite such as water impermeability, water absorption, or volume changes. These properties are vital for the construction of white boxes. In this paper, the suitability of the mutual combination of active and internal additive will also be evaluated.

Abstract: Additive manufacturing is a technology that is influencing every facet of manufacturing such as casting. 3D printing in particular has the potential to revolutionize castings in terms of precision and time taken in production. Patternless molds increase the efficiency of the casting process for large scale manufactured components. Therefore, ceramic based molds can be utilized for low temperature alloy parts such as mounting brackets. Nowadays, 3D printing technologies allow the direct printing of these molds. This is possible with the aid of CAD modelling of the casting mold which allows instant printing of patternless molds. The aim of this work is to introduce an approach to prepare a 3D design for a casting mold that can be manufactured using 3D printing technology. Mold design was made using Solidworks software according to standardized calculations from which cope and drag components were extracted. Candidates for potential mold material are highlighted along with advantages & limitations of utilizing 3D printing methodology.

Abstract: This research studies on the effect of additive (Dolomite) on Biomass powder (Cassava rhizome) which passes Torrefied process and fixed bed at 250 degrees Celsius for one hour and a half. The gasifier with up-draft type was used in this experiment. Air pressure was fixed at 0.1 Bar. The useful heat (Q_useful) and Low heating valves (LHV) was investigated by using an Automatic Bomb Calorimeter. Moreover, the dolomite was varied 0, 10 and 15% by weight mixed with Cassava rhizome achieved with Torrefied process. When Low heating valves (LHV) slightly decreases from 21.96±0.22 MJ/kg to 18.15±0.50 MJ/kg, Q_useful heat from the burning from gasifier sharply increase when it is mixed with dolomite from 753.34±39.18 to 1,003.97±33.49KJ respectively. The loading of dolomite has significance affecting the useful heat. The present study reveals that low heating valves (LHV) decreases and Q_useful heat increase result from dolomite which gives a clean gas product and the Tar molecule can be easily broken. The CO₂ gas from the combustion process was absorbed by CaO, which is the main component in dolomite. The cost of mixing 8.9% of Dolomite with Cassava rhizome is the optimum ratio for the biomass combustion process.

Abstract: We have studied the effect of lead (II) cyanate Pb (OCN)₂ additive on photovoltaic properties of inverted planar solar cells based on inorganic-organic hybrid perovskite CH₃NH₃PbI₃. The active layers of the solar cells were fabricated with a reaction between CH₃NH₃I and a mixture of PbI₂ and Pb (OCN)₂. The highest power conversion efficiency was 15%. Hysteresis behaviors in JV curves were reduced. The lifetime of the solar cells was dramatically increased. SEM images indicated that crystallite sizes were enlarged. The OCN groups were not incorporated into crystals from infrared measurements. These results suggest that Pb (OCN)₂ affect mainly the crystallization process of CH₃NH₃PbI₃.

Abstract: The use of better materials is essential for the development of a country, that is why in this work we analyze a mixture of cement-based mortar with an addition of mucilage from a plant called Maralfalfa, said plant is used as feed for cattle and it is thought that its hydrate content can improve the water-cement reaction. Two mixtures were made, one control and another with the addition. The material used was: volcanic sand from Michoacán, cement CPC 30R RS, drinking water and the addition of mucilage. Cubic specimens (5x5x5 cm), prismatic specimens (4x4x16 cm) and briquettes were made, which were tested at 7, 14, 21, 28, 45 and 70 days of age. The tests performed were non-destructive (density, ultrasonic pulse rate and electrical resistivity) and destructive (simple compression, flexion and tension). The density results indicate that the mixture with addition densifies the cement matrix, the ultrasonic pulse velocity results are very similar between the mixtures, the results of electrical resistivity indicate that the control mixture is slightly higher. In terms of simple compression and flexion, it is indicated that the mixture with the addition was higher than the control, whereas the voltage results indicate the opposite. In addition, it was found that the addition retards the setting time of the mixture.

Abstract: This paper focuses on the problems of ash deposition and corrosion caused by alkali metal chloride in biomass boiler. Kaolin, pulverized coal ash, silica fume, dolomite, limestone and bauxite are used as additives in this study, to investigate the degree of corrosion of four metal materials on biomass boiler. The results show that the corrosion rate of metal samples is significantly reduced after adding additives. Kaolin, pulverized coal ash, silica fume and bauxite show much obvious effect on corrosion inhibition. Corrosion resistance of four pipe metals: T91>15CrMoG>12CrMoVG>20G, in which the corrosion resistance of T91 is much better than the other three metals.

Abstract: Pulverized coal ash can be used as an additive to reduce corrosion on heating surface of biomass boiler. Biomass ash and pulverized coal ash were mixed and coated on the metal surface for experiment; the results showed that the corrosion rate of the metal decreases by adding pulverized coal ash. With the increase of additive content, the corrosion gradually reduces. The effect of different pulverized coal ash on corrosion is different, but as the proportion of pulverized coal ash increases, the effect tends to be close. When the molar content of (Si+Al)/(Na+K) is about 2 and the ratio of Si/Al is about 1, the pulverized coal ash additive works best.

Abstract: Fine-grained fiber concrete used in 3D printing is significantly different from conventional heavy concrete, which is determined by the increased consumption of cement, low water-cement ratio and the absence of large aggregates. The largest grain size of fine aggregate is selected taking into account the thickness of the section, the frequency and type of reinforcement, as well as the method of concrete placement. Despite the fact that the tensile strength of concrete on fine sand is more than 1.5 times higher than the strength of concrete on coarse sand, while there is a decrease in compressive strength. Due to the peculiarities of the technology of concrete manufacturing for layering, the use of coarse sands is impractical, and therefore it was decided to use quartz sand with a particle size module of 1.12 as a filler.

Abstract: The effectiveness of silica fume for the fine-grained concrete used for 3-D technologies is proved in the give scientific paper. The advantages of silica fume using for concretes are presented. The mathematical modeling is used for the fine-grained concrete high-quality compositions’ development. The effectiveness of silica fume has been proved by the studies. The increase in the strength characteristics of concrete with the addition of silica fume is explained by the active pozzolan reaction, which starts when the concrete mix is ​​mixed with water.

Abstract: Indonesia with abundant limestone raw materials, lightweight brick is the most important component in building construction, so it needs a light brick product that qualifies in thermal, mechanical and acoustic properties. In this paper raised the lightweight brick domains that qualify on the properties of thermal conductivity as building wall components.The advantage of low light density brick (500-650 kg/m³), more economical, suitable for high rise building can reduce the weight of 30-40% in compared to conventional brick (clay brick). To obtain AAC type lightweight brick product that qualifies for low thermal and density properties to the effect of Aluminum (Al) additive element variation using artificial neural network (ANN). The composition of the main elements of lightweight brick O (29-45 % wt), Si (25-35% wt) and Ca (20-40 % wt). Mixing ratio of the main element of light brick (Ca, O and Si) with Aluminum additive element (Al), is done by simulation method of artificial neural network (ANN), Al additive element as a porosity regulator is formed. The simulation of thermal conductivity to the influence of main element variation: Ca (22-32 % wt), Si (12-33 % wt). Simulation of thermal conductivity to effect of additive Al variation (1-7 % wt). Simulation of thermal conductivity to density variation (500-1200 kg/m³). The simulated results of four AAC brick samples showed the thermal conductivity (0.145-0.192 W/m.K) to the influence of qualified Aluminum additives (2.10-6.75 % wt). Additive Al the higher the lower density value (higher porosity) additive Al smaller than 2.10 % wt does not meet the requirements in the simulation.Thermal conductivity of AAC light brick sample (0.184 W/m.K) the influence of the main elements that qualify Ca (20.32-30.35 % wt) and Si (26.57 % wt). Simulation of artificial neural network (ANN) of light brick shows that maximum allowable Si content of 26.57 % wt, Ca content is in the range 20.32-30.35 % wt, and the minimum content of aluminum in brick is light at 2.10 % wt. ANN tests performed to predict the thermal conductivity of light brick samples obtained results of the average AAC light brick thermal conductivity of 0.151 W/m.K. The best performance with Artificial Neural Network (ANN) characteristics has a validation MSE of 0.002252.