Papers by Keyword: PAC

Abstract: The urban surface contains a large amount of asphalt concrete pavement, which is also one of the main causes of the urban heat island effect. This study aims to explore the effect of BOFS on radiative cooling when applied to asphalt concrete pavement, and to review it as strategies to mitigate the urban heat island effect. This study chooses the density grading certified by TAF commonly used by road design units at present. Setting up thermometers on the actual construction site, the temperature of each layer would be measured. It is hoped that through comparison at actual on-site paving of BOFS pellets and natural pellets, the difference in effectiveness in radiant cooling can be evaluated. The results show that BOFS pellets for road paving have significant potential for radiative cooling.

Abstract: In this study the performance of biocoagulant based on protein (Moringa oleifera, Vigna sinensi) and tannin (Colocasie esculenta) was compared with Poly Alumunium Chloride (PAC) as a chemical coagulant have been evaluated using a synthetic kaolinite-turbid water which referred to water sample. The effectiveness of biocoagulants dosage were evaluated by turbidity removal (%), total dissolved solid TDS and electrical conductivity (EC). The results showed that the turbidity removal of water sample achieved as much as 94.4% and 87.0% for Moringa oleifera and Vigna sinensi, but low turbidity removal occurred when using Colocasia esculenta as much as 26.4%. High results of turbidity removal showed when using PAC as coagulant at different dosages as a comparison. The decreasing of TDS and EC in the water sample did not much influenced by the coagulants except for Vigna sinensi.

Abstract: According to the problems exist in cyclic utilization of washing wastewater, the coagulation tests utilizing ferric trichloride (FeCl3), alums, poly aluminium chloride (PAC) and polyacrylamide (PAM) are studied, respectively. Experimental results show that PAC was much better than the other coagulants in the removal of LAS and chroma as a single coagulant. Cast 2.5mL PAC(10%) into quantitative washing wastewater, the removal rate of LAS and chroma reach 82.5% and 87.8%, respectively. When mix the every two kinds of coagulants, maintaining the same total amount of coagulant to 2.5mL, cast1.0mL PAC(10%) and 1.5mL alum (10%) into washing wastewater ,the removal rate of LAS and chroma reach 84.1% and 90.0%, respectively.

Abstract: This article studied effluent water quality and membrane fouling by adding different concentration of polyaluminium chloride (PAC) into the submerged membrane bioreactor (MBR) in different dosing ways, and examined the effects on coagulation by adding Ca²⁺. Experiment results show that dosing ways of PAC have no significant influence on CODCr and NH3-N. When the concentration of PAC was 45mg/L and the continuous dosing way was chosen, the average concentration of pollutant was lowest, total phosphorus (TP) removal efficiency was highest, and the membrane fouling was effectively slowed. When the Ca²⁺ concentration was 20mg/L, the coagulation effect was the best, water quality was stable, and the membrane fouling was largely reduced.

Abstract: This paper first introduces PAC dosing system, then research the feasibility of the project goal. confirmed the goal can be achieved. Research on the project, and analysis the process of this project, and implementation finally. After the PAC dosing filter automatic cleaning device completed, control charts are used to verify the device, results show that, PAC amount is controlled in the range of 1.8~2.2mg/L, COD is above 35mg/L.

Abstract: Diffusion of impurity atoms depends on the sublattices occupied, active diffusion mechanisms, and jump frequencies to neighboring sites. The method of perturbed angular correlation of gamma rays (PAC) has been applied over the past decade to study impurity diffusion through measurement of nuclear quadrupole interactions (NQI) at nuclei of ¹¹¹In/Cd probe atoms. Extensive measurements have been made on highly-ordered compounds having the L1₂ crystal structure, including In₃R, Sn₃R, Ga₃R, Al₃R and Pd₃R phases (R= rare-earth element). Measurements in thermal equilibrium at high temperature served to determine lattice locations of ¹¹¹In parent probe-atoms, through characteristic NQIs, and to measure diffusional jump-frequencies of ¹¹¹Cd daughter probe-atoms, through relaxation of the NQI. This paper summarizes results of the jump-frequency measurements and relates them to the conventional diffusivity that can be determined, for example, from penetration profiles of tracer species. In spite of chemical similarities of the series of rare-earth phases studied, remarkably large variations in jump frequencies have been observed especially along series of In₃R and Pd₃R phases. Most phases appear as “line compounds” in binary phase diagrams, but large differences in site-preferences and jump-frequencies were observed for samples prepared to have the opposing limiting phase boundary compositions. Comparisons of jump-frequencies measured at opposing boundary compositions can give insight into the predominant microscopic diffusional mechanisms of the impurity. A change in diffusion mechanism was proposed in 2009 to explain jump-frequency systematics for In₃R phases. An alternative explanation is proposed in the present paper based on site-preferences of ¹¹¹Cd daughter probes newly observed along the parallel Pd₃R series. The diffusivity can be expressed as the product of a jump-frequency such as measured in these studies and a correlation factor for diffusion that depends on the diffusion mechanism. The correlation factor can be modeled for the L1₂ structure and diffusion sublattice of interest using a five-frequency model originally proposed for metals. Although the correlation factor is an essential parameter for the diffusion of impurities, it has never been measured. It is suggested that values of the correlation factor can be determined feasibly by combining results of jump-frequency measurements such as the present ones with diffusivity measurements made for the same host-impurity systems.

Abstract: In this paper, poly aluminium chloride (PAC) was used to remove phenol and aniline from the aqueous phase .The adsorption properties of this process was investigated by zeta potential measurement, infrared spectroscopy and the analysis of pollutants structure and adsorption kinetic. The results described that not only electrostatic attraction but hydrogen adsorption were the main mechanism of both the phenol adsorption and the aniline adsorption. The pseudo second-order kinetic equation could best describe these two adsorption kinetics. The calculated activated energy of adsorption processes of phenol and aniline were 47.2KJ/mol and 44KJ/mol, respectively, which indicated that the adsorption process was chemisorption. Friedrich model was fitter to describe the adsorption isotherm of these two adsorption processes.

Abstract: Using grid flocculation technology inspected the effect of treatment of sewage by the addition of coagulant PAC. After the device is stable, under the 40 mg/L of dosage and 17.1 min of flocculation time conditions, the removal of turbidity, COD, NH₃-N and TP is 72%, 48%, 13.8% and 77%.

Abstract: Beginning during the decade of 1920, the Brazilian highway system became the main way of transportation in the country, fomenting the search for asphaltic mix with better mechanical properties and resistance to the weather variations. The asphaltic mix is formed by minerals aggregates and binder (PAC Petroleum Asphaltic Cement). The aggregates are responsible for supporting the traffic weight and stability. The PAC is responsible for the attachment between the constituent particles and impermeable state. In this work it was investigated the formulation of asphaltic mix starting from the packing equations of the particles: Andreasen, Alfred and Alfred Inverted. It was produced bodies of proof varying the proportions of the aggregates and fillers, keeping constant the PAC (5% in weight) and the results were compared to an industrial standard formulation. The values obtained are in accordance with the DNIT norms, indicating that the equations of packing can be applied to the formulation of asphaltic masses.

Abstract: The inclusion of alternative materials in the composition of asphaltic masses aims to solve the problems arising from the disposal, in the environment, of industrial waste discarded; however, to ensure that such inclusion doesn't damage the characteristics and properties of the asphaltic mass, it is necessary that the mixtures, composed by mineral aggregates, PAC and filler, are previously submitted to the standardized essay. It is known that the filler is mainly responsible for the absorption of the PAC and that, the greater the amount of the PAC utilized on the asphaltic mass, the bigger the costs. Thus the characteristics of the filler, as well the rate of packing of the constituents of the asphaltic mass affects directly the cost and properties of the final product. Given the previous subject, in this work it was aimed to study the effect of the addition of low plasticity clay and peat in the final properties of the asphaltic masses.