Papers by Keyword: Sucrose

Abstract: This study is to determine the effect of graphite as reinforcement material on natural resources carbon foam on the mechanical and physical properties. Sucrose is used as carbon precursor and graphite with various concentration from 0 wt% to 0.3 wt% was added into the carbon foam. Carbon foam was prepared by using template method followed by pre curing and carbonization process. Pre curing process was take place at 250°C and carbonization process was carried out at 900°C under inert atmosphere. The morphology, porosity, density and compressive strength were characterised in this experiment. Through Scanning Electron Microscope (SEM), graphite can be seen clearly embedded into the ‘window’ and fill the void space. Porosity of carbon foam decrease when the concentration of graphite increase and the density of carbon foam increase when the concentration of graphite increase. Carbon foam with 0.3 wt% graphite added shows the highest compressive strength (1.84 N/mm²) compared with carbon foam without graphite added (0.95 N/mm²). The properties of carbon foam are significantly influenced by the addition of graphite loading.

Abstract: The fast precipitation of ettringite in conventional Calcium Sulfo Aluminate (CSA) cement causes rapid stiffening of the cement paste and is directly associated with short setting times and self-desiccation. To extend the time during which those types of cement remain workable, retarding admixtures can be used. However, retarders may affect the amounts and types of hydration products formed and as a consequence the ability of hydrated cement to chemically bind water. This work investigates the influence of two natural-based admixtures on the self-desiccation ability of a vernacular CSA ternary binder used as earth stabilization. Vicat measurements were used to study the efficiency of citric acid and sucrose as retarding admixtures on the setting time of stabilized earth. A quantitative study of the self-desiccation ability of the binder was performed on dried binder pastes using thermogravimetric analysis (TGA). Results show that both admixtures have a significant impact on the setting time of the binder. Furthermore, TGA showed that the self-desiccation ability of this vernacular CSA binder is significantly reduced when citric acid at high dosages is used, both at early hydration and after 14 days. On the contrary, the use of sucrose does not affect the water chemically bound at an early age but can maximize bound water after 14 days of hydration.

Abstract: The goal of this study is to experimentally evaluate the performance of sucrose and lignosulfonate acid as a concrete retarder. The initial and final setting times of concrete are obtained for various dosages of those admixtures. Besides, the impact of those retarders to the compressive strength of concrete is also explored. A total of 13 (thirteen) mix samples are made, in a laboratory, by adding various dosages of those admixtures into the reference mixtures. Those samples are tested using a concrete mortar penetrometer and a compression-testing machine to obtain their setting times and compressive strengths. Sucrose addition with a dosage of 0.01%, 0.014%, and 0.019% (by weight of cement) increases the initial setting time by 102.67%, 117.54%, and 138.89% and extends the final setting time by 57.70%, 72.83%, and 99.47%. The addition of liquid lignosulfonate acid by 0.6% (by weight of cement) causes the initial setting time to grow by 68.77% from 4.46 to 7.52 hours. Similarly, the final setting time is prolonged by 51.65% from 7.27 to 11.02 hours. This study confirms that sucrose is more effective than lignosulfonate acid in term of retarding concrete setting. However, careful attention is needed when applying sucrose as a set retarder because applying larger than a critical dosage results in an adverse effect. Sucrose is also an effective strength reducer for concrete. The 28-day strength reduces by 10 to 25% due to adding sucrose as much as 0.019% (by weight of cement).

Abstract: Silicate micro- and nano-additives are multifunctional in relation to cement systems. Their application can solve a wide range of technological problems while maintaining the economic efficiency of technical solutions. The effect of silicate additives and fillers is determined by their level of dispersion, due to which the technologies for producing nano- and submicro-sized dispersed materials are being developed. The combination of mechanochemical synthesis of modified calcium hydrosilicates with subsequent thermolysis makes it possible to produce calcium silicate dispersions (SCD), which differ in polymodality of the fractional composition including submicro (10^–7–10^–6 m) and microdimensional (≥10^–6 m) modes. The main element of the technology is the use of modifying carbohydrate, which acts as a stabilizer of hydrated phases of silicates. A comparative study of SCD produced using sucrose (sSCD) and lactose (lSCD) revealed the effect of these carbohydrates on the properties of sSCD and lSCD, as well as their effectiveness as a component of cementitious composite binder. It was found that the level of adsorption of modifying carbohydrate determines the physical properties of SCD (granulometry, specific surface area). The relatively high residual content of free sucrose (0.24%) in the composition of sSCD prevents the consolidation of silicates nanoparticles formed during the thermolysis, causes a high content of submicro sized fractions and a high specific surface area with sSCD (26.3 ± 0.7 m²/g). Lactose is absorbed by the silicate phase; the residual content of free lactose does not exceed 0.028% of lSCD. The low content of stabilizing carbohydrate contributes to the development of nanoparticle consolidation, a decrease in the specific surface area of lSCD to 13.0 ± 0.2 m²/g and content of submicrosized fractions. The residual content of free carbohydrates and particle size characteristics of sSCD and lSCD determine the nature of their influence on Cement-SCD-based concrete setting and hardening. The presence of residual sucrose in the composition of sSCD and fine fractions determines the competitive nature of the processes of retardation of hardening and acceleration of hardening of the cement system due to the nucleation effect, as a result of which the curve of the setting time is extreme. In addition, the inhibitory effect of sucrose reduces the strength of concrete on the 7^th day. By the 28^th day, the inhibitory effect of sucrose has been overcome, and concrete samples demonstrate an 18% increase in compressive strength with a sSCD content of 30%. The low content of residual free lactose in the composition of lSCD causes the nucleation effect. As a result, there is a monotonous reduction in the setting time of concrete mix with an increase in the content of lSCD in the composition of HF, as well as a significant increase in concrete strength (up to 127%) on the 7^th day. At the same time, on the 28th day the strength of concrete increases slightly

Abstract: Mature coconut water is always been thrown away as a waste. However, it contain a lots of nutritional elements such as amino acids, pytohormones and minerals. Plant needs some essential nutrients besides pytohormones for their growth and development. In this study, the effect of waste mature coconut water and sucrose was observed on the micropropagation of dragon fruit tree (Hylocereus polyrhizus). The stem was inoculated on MS medium containing Benzyleaminopurine (BAP) 0.03mg/L BAP and 0.01mg/L Naphthaleneacetic acid (NAA) supplemented with waste mature coconut water in various concentrations (0%, 2%, 4% and 6% v/v) and with various concentrations : 0%, 1%, 2% and 3% of sucrose respectively. As the concentration of the waste mature coconut water and sucrose increased up to 4 % and 3%, increase in the elongation of the stem and the number of root regenerated per explant was observed repectively. In conclusion, waste mature coconut water has enhanced the elongation of the shoots but has not promoted on the root induction with the suitable amount of sucrose.

Abstract: The present study focuses on characterization the physical properties of liposome formulation which was dispersed in HPMC matrix and lyophilized in the presence of disaccharides. The lyophilized formulations featured cationic dimethyldioctadecylammonium (DDA) to produce dry solid and overcome limitations in terms of detrimental phase separation in phospholipid membranes during production process. Disaccharides, such as sucrose and lactose, have been reported to protect phospholipid membranes during drying, while HPMC was used as dispersed matrix to inhibit recrystallization of disaccharide. Their physical properties were characterized including their morphology using scanning electron microscopy (SEM), crystallinity using x-ray diffractometry (XRD), and solid phase separation using differential scanning calorimetry (DSC). On the basis of these evaluations it was found that the presence of sucrose and HPMC in the formulation showed a miscible mixture and relatively less crystalline-forming properties compared to those using lactose, thus potentially construct a stable dried liposomal formulation. The present study reveals prospective advantages of using combination of sucrose and HPMC in development of dried–DDA liposomal formulation.

Abstract: Through yield and Sauter mean diameter, the sucrose crystallization was studied in vibrated bed equipment, in which, supersaturation degree, dimensionless vibration number and crystallization time were independent variables. A central composite design with seventeen trials was performed in order to ascertain the influence of each variable in both responses, the crystallization temperature and the amount of seeds were kept constant. The crystallization vibration system differs from the usual configuration, consisting of two perforated discs made of stainless steel, one loop and three aluminum rings. By canonical analysis, it was obtained the operating condition which maximizes the yield and average crystal size. Surface responses were also obtained according to the relevance of each variable, in which were evidenced the high supersaturation and vibration influence for both factors, the high quadratic term of all variables on the crystal yield, and also highlights the great interaction between supersaturation and the dimensionless vibration number.

Abstract: In this work, the effects of sucrose on setting time, heat of hydration and hydration products were studied, and the corresponding hydration process and regulation mechanism were discussed. With the adsorption test of sucrose on Ca (OH)₂ suspensions, the “wake up” mechanism of Ca (OH)₂ on sucrose-retarded cement was discussed. The results indicate that sucrose is used as retarder to increase the dormant period by adsorption to the cement surface, but there exists a critical amount of sucrose. And the XRD patterns indicate that sucrose can accelerate the reaction of C₃A and the formation of AFt, but restraint the hydration of C₃S. Ca (OH)₂ that was used as accelerator in this paper can adsorb the sucrose up to 6.2mg sucrose/g Ca (OH)₂. The combined-use of sucrose and Ca (OH)₂ does not change the shape of the heat rate curves significantly. And the dormant period of sucrose-retarded cement can be decreased with the doses of Ca (OH)₂ increasing, because of its high surface and preferential adsorption of sucrose.

Abstract: Alkali-activated materials are formed by the alkaline activation of inorganic materials and are characterized by the wide range of potential use. The objective of experiment was to investigate the possibility of use fine-grained alkali activated composites in the construction industry. Selected properties of alkali-activated systems based on granulated blast furnace slag and fine-grained aggregates were determined. At the beginning of the experiment, different samples prepared of 3 types of activators were tested, basic properties (time of workability, initial and final setting time, compressive and flexural strength) and also a possibility of selected retarder use was determined. Then, samples with the best potencial to presumed use were tested in detail and a possibility use as a substitute for selected construction materials were evaluated. On the basis of determined properties, prepared composites could be used as reprofiling mortars, materials for cracks repairing or socle plasters.

Abstract: A novel process for the preparation of a nickel foam from nickel oxide has been studied. The solid organic foam prepared by the thermo-foaming of a nickel oxide powder dispersion in molten sucrose is heat treated at the 1000 °C in an inert atmosphere to produce the nickel foam. The nickel foam produced has interconnected cellular structure with porosity ~ 94%.