Thermodynamic properties and phase diagrams of spin-1 quantum Ising systems with three-spin interactions

The spin-1 quantum Ising systems with three-spin interactions on two-dimensional triangular lattices are studied by mean-field method. The thermal variations of order parameters and phase diagrams are investigated in detail. The stable, metastable and unstable branches of the order parameters are obtained. According to the stable conditions at critical point, we find that the systems exhibit tricritical points. With crystal field and biquadratic interactions, the system has rich phase diagrams with single reentrant or double reentrant phase transitions for appropriate ranges of the both parameters.Comment: 10 pages, 5 figure

Photodegradation of Dyes Using Titanium Dioxide Supported on Glass

Photodegradation of dyes, in aqueous solution was carried out using titanium dioxide coated on glass plates, illuminated by blue fluorescent lamps. TiO₂ coated glass was prepared by sol-gel technique. Air was pumped into the mixture to ensure continuous supply of oxygen in the mixture. Methylene blue removal was studied based on the effect of amount of coated TiO₂ sol-gel, initial concentration, light intensity, light source, and pH of solution medium. Comparison was also made to the powder form of TiO₂ which was prepared by the same method. The highest percentage of methylene blue removal was obtained when the photodegradation experiment was run using 5 pieces of TiO₂/Glass (4 times of sol-gel dip-coating) and 10 ppm of methylene blue solution at 28°C after illumination under 4 white fluorescent lamps of 20 W for 4 hours. About 84% of methylene blue was removed. Methylene blue removal was found to be efficient and comparable to the illumination using near UV light, sunlight, 4 white fluorescent lamps, 4 dark fluorescent lamps and 4 blue fluorescent lamps

Photodegradation-Adsorption of Organic Dyes Using Immobilized Chitosan Supported Titanium Dioxide Photocatalyst

The combination effect of photodegradation-adsorption using the immobilized TiO2 and chitosan supported on glass (TiO2-Chitosan/Glass) under the illumination of light with suitable energy ( hν > Ebg ) as a new method for the treatment or pre-treatment of dye-containing wastewater has been studied. The prepared photocatalyst was characterized by scanning electron microscopy, X-ray microanalysis, X-ray diffraction analysis, Fourier transform infrared spectroscopy, surface area and porosimetry analysis and thermogravimetric analysis. Methyl orange (an anionic dye of the monoazo series) removal was studied based on the effect of TiO2 : Chitosan ratio, photocatalyst loading, initial concentration, light intensity, different light source, temperature and pH. Comparison was also made to dyes with different characteristics, namely methylene blue (a cationic dye) and mixed dyes (a mixture of methyl orange and methylene blue). Methyl orange removal was optimum when the experiment was run using 5 pieces of 4 dip-coated TiO2-Chitosan/Glass (45 mm X 80 mm X 2 mm) and 500 ml of 20 ppm methyl orange solution at 40 °C under the illumination of a 230 V near UV lamp for 6 hours. About 87.0 % of 20 ppm methyl orange can be removed successfully with approximately 9.2 % removal efficiency attributable to photodegradation process and another 77.8 % attributable to adsorption process. Comparatively, approximately 93.8 % or 18.51 ppm of methylene blue can be removed by applying the same condition with approximately 43.7 % removal efficiency attributable to photodegradation process and another 50.1 % attributable to adsorption process. The solution pH was found to have a significant and yet complex effect. Solutions with pH 4.0 – 6.0 and 10.0 – 12.0 were found to be the optimum range for methyl orange and methylene blue respectively. In view of the electrostatic attraction between the catalyst and substrates, the ionic characteristic of the dyes is suggested to play an important and selective role in both the photodegradation and adsorption processes. The adsorption of model pollutant solutes on the prepared TiO2-Chitosan photocatalyst surface leads to the effective photodegradation process. Removal rate of methyl orange and methylene blue were studied based on the integrated form of Langmuir-Hinshelwood kinetic equations. The photodegradation-adsorption process obeys first order kinetics for the first 60 minutes. After that, it was most likely to be affected by the solution pH and the nature of the photocatalyst. This is obvious based on the effect of pH for MO and MB removal, in which the obtained data cannot fit nicely into the kinetic model or its linearized form. Although Total Organic Carbon (TOC) and Gas Chromatography-Mass Spectrometry (GS/MS) coupled with Direct Insertion-Mass Spectrometry (DI/MS) analyses had confirmed the successful break up of methyl orange and methylene blue ‘parent molecule’, successful destruction of methylene blue aromatic rings is quite difficult to achieve. Nevertheless, the combined photodegradation-adsorption system still appears to be an efficient accelerated removal process of organic pollutants from waste water

ERP implementation planning : a critical success factors (CSFs) approach

Enterprise Resource Planning (ERP) is an integrated set of software modules which are linked to a common database to handle basic corporate functions such as planning, manufacturing, sales, marketing, accounting, distribution, human resource and inventory. When ERP is implemented successfully, it can reduce operating costs, increase productivity, and improve customer services. However, ERP fails to deliver the promised benefits in many companies due to the poor implementation planning. A successful ERP implementation requires a careful thinking, good planning from a strategic perspective. It is difficult to measure the success of an extremely complex information system such as ERP as it involves almost every aspect of business operations. Different people from different perspectives will have different views about the success of ERP implementation. Therefore, we adopted Critical Success Factors (CSFs) approach. We identified the critical success factors for the success implementation of ERP based on literature review. A model is developed with assumption that there is Relative Importance (RI) among these critical success factors. The data collected in Chinese Mainland manufacturing companies were analyzed on Structural Equation Modeling by LISREL. Six critical success factors were identified by the survey as the relative important critical success factors. They are (1) Business Process Reengineering management, (2) change readiness, (3) software competence and IT skills, (4) departmental communication, (5) top management support, and (6) hardware and equipments. Understanding the importance of these factors will help managers to make a good planning for ERP implementation. It is suggested to set high priority to these critical success factors, which can help managers to have a better control of the activities in the process of ERP implementation. Hopefully, it will increase the chance to implement ERP successfully

Gamma-ray emission from globular clusters

Over the last few years, the data obtained using the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope has provided new insights on high-energy processes in globular clusters, particularly those involving compact objects such as Millisecond Pulsars (MSPs). Gamma-ray emission in the 100 MeV to 10 GeV range has been detected from more than a dozen globular clusters in our galaxy, including 47 Tucanae and Terzan 5. Based on a sample of known gamma-ray globular clusters, the empirical relations between gamma-ray luminosity and properties of globular clusters such as their stellar encounter rate, metallicity, and possible optical and infrared photon energy densities, have been derived. The measured gamma-ray spectra are generally described by a power law with a cut-off at a few gigaelectronvolts. Together with the detection of pulsed gamma-rays from two MSPs in two different globular clusters, such spectral signature lends support to the hypothesis that gamma-rays from globular clusters represent collective curvature emission from magnetospheres of MSPs in the clusters. Alternative models, involving Inverse-Compton (IC) emission of relativistic electrons that are accelerated close to MSPs or pulsar wind nebula shocks, have also been suggested. Observations at >100 GeV by using Fermi/LAT and atmospheric Cherenkov telescopes such as H.E.S.S.-II, MAGIC-II, VERITAS, and CTA will help to settle some questions unanswered by current data.Comment: 11 pages, 7 figures, 2 tables, J. Astron. Space Sci., in pres

The Status and Progress of Resource Utilization Technology of e-waste Pollution in China

AbstractIn this paper, the current status and the characteristics of e-waste were presented. The hazards of electronic wastes, significance of their recycle, resource utilization technology at home and aboard are summarized in this paper. Several recycling methods were introduced such as recycling of metals, plastics and glass, etc. The way of comprehensive utilization to e-waste in China was pointed out