Papers by Keyword: Granules

Abstract: This paper is devoted to obtaining and investigating polymer composites based on polyamide-6 and carbon nanotubes. Polyamide 6, type 210/310, was used as a polymer matrix, and carbon nanotubes manufactured by OcSiAl were used as a modifier. The components were compounded in a co-rotating twin-screw extruder HAAKE Rheomex OS PTW 16 to obtain granulate. The granulate was processed by injection molding on a Babyplast 6/10V machine to obtain test samples as double-sided blades (ISO-527-2, type 5A). Elastic strength tests were carried out on a Gotech UAI-7000M universal tensile-testing machine. It has been shown that introduction of 0.15% CNT promotes an increase in the yield point and the initial modulus of elasticity with a significant decrease in the ultimate strength. The maximum value of the tensile strength (161 MPa) has been obtained for the specified composition at an injection rate of 12.9 ml/s.

Abstract: A steel slag has been treated by air granulation, in order to enhance cementitious properties of the slag. Two samples with sizes ranged 1.68-2.38mm and 212-297μm and coded as Slag A and Slag B, respectively, were chosen from the granulated slag for investigations. A sample of the original steel slag was also studied. XRD analyses indicated the formations of α-C₂S, β-C₂S, C₂F, C₂MS₂, f-MgO and α-C₂S, C₂F, f-MgO in Slag A and Slag B, respectively. The phases in the two slag samples were quite different from the phases found in steel slag. The SEM results show a reduction of C₂S sizes from 10-20μm for the steel slag to nano-scales by air quenching for Slag B. This treatment of air quenching has increased the cumulative heat of hydration to 105.35J/g measured for Slag B, almost two times greater than that of the steel slag. The study results demonstrate a high potential for utilizations of the steel slag in cement and concrete applications after the slag treatment by air quenching. The treatment may thus lead to an environmental friendly and cost-effective recycling for the steel slag. This can also contribute to the sustainable developments in the steel and cement/concrete industries.

Abstract: The purpose of this study was to prepare biphasic granules containing gypsum and carbonated apatite at low temperatures. The biphasic granules were prepared using dissolution-precipitation technique at three different temperatures 30°C, 40°C and 50°C. Characterization of the biphasic granules was determined by multiple analytical methods such as X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infra-red (FTIR), and CHN Analysis. The obtained granules were determined by XRD as biphasic granules containing bone apatite and gypsum. The cross-section of biphasic granules was observed by SEM. The formed bone apatite was identified as B-Type carbonated apatite using FTIR The carbonate content in biphasic granules fabricated at 30°C, 40°C and 50°C were recorded by CHN analysis as 5.0 wt%, 6.1 wt% and 6.25 wt%, respectively.

Abstract: Objective: To investigate the formulation and technology for taste-masking granules. Methods: Clarithromycin was used as a model active pharmaceutical ingredient with bitter taste. Four preparation processes were compared, which were gelatin mono-condensation microcapsule method, calcium alginate microcapsule method, gelatin microsphere method and resin matrix granulation method. With taste masking effect and dissolution rate as evaluation indexes, the optimal preparation technology was studied. The orthogonal experiment was used to investigate the optimal formulation. Results: Clarithromycin granules prepared by the resin matrix granulation method had good taste masking effects and suitable dissolution rate. The optimal formulation was following: polyacrylic acid resin IV 0.85 g, PEG4000 0.30 g, sodium bicarbonate 0.10 g. The prepared clarithromycin granules have good taste masking effect and its dissolution in 45 min can reach 80.5%. Conclusion: The optimal formulation and technology can satisfy the request for taste masking and dissolution rate of clarithromycin granules.

Abstract: Calcium phosphates (CaPs) are synthetic bone grafting materials. CaPs are an alternative to overcome the drawbacks present with autologous bone grafting and/or xenograft materials. Among the CaPs, tricalcium phosphate (TCP) stands out as a good candidate due to its physicochemical properties. The clinical performance of β-TCP has already been proven and established. Nevertheless, the format in which TCP is delivered is also important in terms of clinical handling. This work assessed the in vivo performance of TCP-based bone grafting materials with different formats. Materials studied were a TCP paste (TCP-P), a TCP foam (TCP-F) and TCP granules (TCP-G). A sheep scapula model was used to evaluate the osteogenic performance of these bone grafting materials. All materials performed well in terms of bone regenerative capacity and material resorption. However, TCP-P and TCP-F displayed a more pronounced initial material resorption and also exhibited better handling properties compared to TCP-G. TCP-based materials with improved handling properties, such as TCP-P and TCP-F, which at the same time possess the advantageous properties of β-TCP are suitable bone substitute materials for grafting and reconstruction of bone defects in numerous clinical applications.

Abstract: This paper describes research on utilization of solid waste materials from mineral wool production. Aim of this research is verification of most suitable way of separated waste material utilization in building materials and determination of its maximal amount without negative effect on physical-mechanical and ecological characteristics of a final product. The research was focused on self-leveling mixtures, thin-walled glass fibre reinforced concrete products and vibropressed thin-walled shaped concrete blocks.

Abstract: Coupled anaerobicaerobic granular bio-film reactor was employed to acclimatize the granules when treating actual coking wastewater. Two oxygenation methods (i.e. A and B) were employed. For method A, dissolved O₂ was supplied to the reactor A (RA) through a continuous oxygenation way of 800-15000mlmin^-1. And for method B, dissolved O₂ of 800-15000mlmin^-1 (18-12 times at 20-60min intervals, 1 h each time) was supplied to the reactor B (RB). The experimental results showed that it took only about 6 months for granules acclimation using actual coking wastewater. With inorganic carbon (NaHCO₃) addition, both oxygenation methods could run well when acclimatizing the granules. However, method A could have comparatively high and stable operation effect. And the continuous oxygenation way was more suitable for the acclimation of the granules when treating actual coking wastewater than the intermittent oxygenation way.

Abstract: The knowledge of the degradation process is an important role to understand and predict in vitro results. Granules of strontium-hydroxyapatite (Sr-HA) were submitted to a degradation process under dynamic conditions using a bioreactor system and using a solution with pH=5. The degradation process under dynamic conditions can be represented by a curve in which the calcium content firstly increases (dissolution part) followed by calcium decreasing (reprecipitation). The use of a low pH solution does not affect the curve’s shape but reduces the precipitation step.

Abstract: Sorption experiments of bovine serum albumin (BSA) on hydroxyapatite (HAp) ceramic granules, prepared at three temperatures 900°C, 1000°C and 1150°C were performed at room temperature 18,6 °C and phosphate buffer, pH 5,83; 6.38 and 7,39. Thermal treatment contributed to the decrease of bovine serum albumin immobilization indicating that sorption process depended on HAp ceramics specific surface area and pH values of phosphate buffer solution. However, it was confirmed that granule size was also an important parameter for bovine serum albumin adsorption. As a result of these experiments, the most appropriate adsorption conditions and phosphate buffer pH values influence on to BSA sorption were analyzed.

Abstract: Hydroxyapatite (HA) is the calcium-phosphate material with composition closest to that of human bone, what makes it suitable for osseous implant purposes, namely as fillers, spacers and bone grafts substitutes. This study is aimed at the development of a method to produce porous spherical hydroxyapatite granules. The process involves the spraying of a suspension with different amounts of a setting agent to a setting media. The tailor and the control of the morphology, size and porosity of the granules were attained by adjusting the nozzle diameter, the pressure of air flow and the distance between the nozzle and the setting media.