Papers by Keyword: MIP

Abstract: In this study, a modified pore structure of cement based material with respect to a path for ingressive ions was established. Of pores in a concrete, gel pores and other entrapped air voids were excluded from modelling the pore structure as no interests are given due to the ions immobilization of cement paste media. To setup the pore structure, the linear traverse method (LTM) was used to distribute air voids along the traverse line in a hexahedron cement paste structure, followed by including entrained air voids to fill up the least space of the cement matrix and making a network of the air voids through capillary pores at the variation in the diameters. Then the mercury intrusion porosimetry (MIP) was used to iteratively approach an accordance rate with calculated one from the above way to get into appropriate convergence value. As a result, for the OPC specimen the developed model shows a somewhat relevant value of 42.4 % of the accordance rate compared to empirical one and 64.24 of the ratio of ionic path to original distance within a concrete.

Abstract: The primary objective of this paper was to study the mechanical properties of the cement stabilized gravel by different compact method which added rubber particles by using macroscopic and microscopic test. Through test of compression, relationships of mechanical properties of samples were studied. Pore structure and fractal characteristic of mixture was analyzed quantitatively using mercury intrusion porosimetry (MIP), scanning electron microscope (SEM) was applied to analyze the micro-morphology of samples. The tests results showed that the compressive strength of samples which prepared by using vibrating method was greater than that by static pressure method. Compressive strength of samples from vibrating method or static pressure method decreased with the rubber particles volume fraction increase. MIP tests showed that the mean pore diameter and porosity of mixture increased from about 70nm to 250nm and 9% to 24% with the rubber particles content increasing, respectively. SEM tests showed that the interface bonding between sand and hardened cement paste was better than that of between rubber particles and hardened cement paste.

Abstract: The Modification mechanism of the Polymer Modified Cement Concrete was studied by the DTA,SEM and MIP with the confirmation of lab test results. The research indicated: the more dosage of the polymer, the less content of the Ca(OH)2 in the Cement hydrated product. The pore structure was improved evidently simultaneously. The polymer film tend to more complete and interweaved with Hydration products. Therefore the netted structure was formed and the flexiblity of concrete was increase greatly. Lab test results also proved it：when continued adding the polymer, the performance of concrete improved remarkably.

Abstract: This article gives a contrast of molecular imprinting affinity purification method (by HPLC) and immunoaffinity column purification method (by HPLC) in the determination of zearalenone in corn. In the determination process, two levels (dosages) of 60μg/kg and 500μg/kg were used. Recoveries of by means of the two methods were 90.4%, 90.1% and 92.9%, 90.7% respectively. And the molecular imprinting affinity column can be reused several times.

Abstract: A new chiral stationary phase for amlodipine (3-ethyl 5-methyl-2 -[(-2-(aminoethoxymethyl)-4-(2-chlorophenyl)-1,4-dihydro-6-methyl-3,5-pyridinedicarboxylate) based on a molecularly imprinted polymer has been prepared by radiation polymerization method and used for chromatographic separation of the chiral enantiomers. The effects on the separation of mobile phase and flow rate were investigated, and the optimum conditions for HPLC were shown to be: mobile phase, chloroform; flow rate, 0.3 ml min-1; at room temperature. The results has shown that the amlodipine-imprinted polymer was capable of recognizing the enantiomeric difference between the template and its R-enantiomer, whereas the non-imprinted and thermal polymerization polymer have no chiral recognition ability for the enantiomers.

Abstract: The effect of mineral admixture and curing condition in pore structure of concrete was studied in this paper. Concrete samples with different component were prepared firstly, and then they were put into standard condition, fresh water and salt environment that produced artificially respectively at 20 °C. After the experiments of curing at 3, 28 and 180 days pore structure were tested by mercury intrusion porosimetry (MIP). The results obtained reveal that with the increase of the age, the pore structure degradation impact in salt environment of concrete increase dramatically. When at 28 days, total pore volume and porosity of concretes in fresh water is lower by 20% and 5% respectively than the ones with larger mean pore size and critical aperture in salt environment, which represents pore refinement in fresh water had a good effect. Compared to the salt environment erosion, it can be found that the impact of pore refinement in fresh water is more significant.

Abstract: In steelmaking plant, the process times of machines change frequently and randomly for the reason of metallurgical principle. When those change happen, the plant scheduling and caster operation must respond to keep the optimal performance profile of plant. Therefore, the integration of plant scheduling and caster operation is a crucial task. This paper presents a mixed-integer programming model and a hybrid optimized algorithm for caster operation and plant scheduling, which combine the genetic algorithm optimization and CDFM process status verification. Data experiments illustrate the efficiency of our model and algorithm.

Abstract: Water transport is an important parameter that affects the long term performance and degradation of concrete greatly. Nowadays, adding fly ash is a promising solution to achieve high-performance, low-price and environment-friendly concrete. To characterize the effect of fly ash on water transport of concrete, especially in dry state, moisture variations and microstructure of concrete with different mix proportions were studied in this paper. Test results reveal that fly ash will increase the porosity of early curing concrete, the higher porosity leads to a faster evaporation, which accelerates the transport of water in cement based materials.

Abstract: The objective of this investigation is to evaluate the effect of surface treatments on cement-based materials, which include mortar and concrete samples. Penetrated sealers and methyl methacrylate (MMA) were used as surface treatment materials. Two concrete mixes (w/c = 0.35, 0.55) were selected and cubic/cylindrical specimens were prepared according to ASTM specifications. The treated specimens have higher compressive strengths than the control specimens. Also, the absorptions and total charge passed of rapid chloride penetration test (RCPT) are lower in the treated specimens. Scanning electronic microscope (SEM) was utilized to estimate the microstructure of the specimens. Denser pore structures and narrower pore-size distribution were observed in SEM micrographs and mercury intrusion porosimetry (MIP) spectrum for the treated specimens, which are correspondent to the macro-observation. The positive effect is most prominent in polymer treated specimens. For higher w/c ratio mix, large capillary pores were filled by most of treatment materials and compressive strength significantly increased, while, for lower w/c ratio mix, polymer and silicate sealer filled in medium capillary pores as indicated by MIP and RCPT results.