365 research outputs found

    Estimating resource bounds for software transactions

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    We present an effect based static analysis to calculate upper and lower bounds on the memory resource consumption in a transactional calculus. The calculus is a concurrent variant of Featherweight Java extended by transactional constructs. The model supports nested and concurrent transactions. The analysis is compositional and takes into account implicit join synchronizations that arise when more than one thread perfom a join-synchronization when jointly committing a transaction. Central for a compositional and precise analysis is to capture as part of the effects a tree-representation of the future resource consumption and synchronization points (which we call joining commit trees). We show the soundness of the analysis

    The pedagogical training management of gifted high school teachers in the region of Red River Delta based on a competency approach

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    Pedagogical training for teachers is always an important issue of every education system. Teachers impart knowledge, give academic advice to students, and assist students in applying knowledge to develop society. This study investigated the gifted high school teacher pedagogical training management in the region of the Red River Delta according to the competency approach. Based on the available data, the research indicated three main things: (i) Professional pedagogical competence of gifted high school teachers; (ii) Pedagogical training activities for gifted high school teachers; (iii) Management of pedagogical training activities for gifted high school teachers. This study conducted a survey of 547 departmental and school managers in gifted high school teachers in nine provinces in Red River Delta, including Hanoi, Ha Nam, Thai Binh, Nam Dinh, Hai Duong, Hung Yen, Bac Ninh, Quang Ninh, and Vinh Phuc. These findings are only preliminary research, and they will be an important basis for proposing management solutions to improve the effectiveness of pedagogical training activities for gifted high school teachers

    ADSORPTION OF MERCURIC ION FROM AQUEOUS SOLUTIONS USING MODIFIED FLY ASH

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    In this study, fly ash was treated with NaOH solution (FAN) before modifying with (3-mercaptopropyl) triethoxysilane - MPTMS (FAMPS). By using FTIR, FESEM, XRD, EDX, and BET techniques, the change in structure, composition and morphology of FAN and FAMPS was evaluated. The FTIR spectra of FAN and FAMPS showed that there is no chemical reaction between the MPTMS and FAN. After modification, the FAMPS has a rough surface with composition difference from the FAN. Mercuric ion adsorption behavior as well as adsorptionisotherm models (Langmuir and Freundlich) of the FAN and FAMPS were also investigated and discussed. Thanks to FAN modification, the mercuric ion removal percent of the FAMPS was higher than that of the FAN. Owing to the adsorption data, Freundlich isotherm modelwas fitted for the mercuric ion adsorption process

    Investigating the diversity of arbuscular mycorrhizal fungi from Gymnema sylvestre and Curcuma longa in Vietnam

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    Arbuscular mycorrhizal (AM) fungi are soil eukaryotes that belong to phylum Glomeromycota and have symbiosis with the vast majority of higher plants’ roots. AM fungi are believed to be coevolved with terrestrial plants, the abundance and diversity of AM fungal communities as a result are host plant dependent. A survey of AM fungi from the rhizospheres of medicinal plants in Northern Vietnam including gurma Gymnema sylvestre and turmeric Curcuma longa was carried out. From the extracted total DNAs of the medicinal plants’ rhizosphere soil samples, 35 mycorrhizal fungal species were identified by analyzing small subunit rRNA gene sequences. Result revealed that genus Glomus is the most abundant in the AM communities of G. sylvestre and C. longa, followed by Gigaspora and Acaulospora. Besides, AM species belonging to genera Scutellospora, Diversispora and Rhizophagus were observed in almost all rhizosphere soil samples. The spore counting by wet sieving and decanting method uncovered a variation in AM spore density of gurma and turmeric rhizosphere. In general, AM species were found more abundantly and more diverse in collected rhizome soil samples of C. longa (27 species belonging to 10 genera) than of G. sylvestre (17 species found belonging to 7 genera). The observed difference in AM communities of G. sylvestre and C. longa supports evidence for the dependence of AM fungal species on host plants, and indicates that AM fungi may have relation to the host plants’ secondary metabolite production

    Using fly ash treated by NaOH and H2SO4 solutions for Hg2+ and Cd2+ ion adsorption.

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    This paper presents the results of adsorption ability of heavy metal ions (Hg2+ and Cd2+) by fly ash (FA) before and after treatment using NaOH and H2SO4 solutions.  Original- and treated FA were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscope (SEM). Specific surface area of FA before and after treatment was calculated by Brunauer – Emmett – Teller (BET) isotherm equation. The obtained results indicated that the morphology and specific surface area of FA changed clearly after treatment by acid or alkaline solutions. Adsorption capacity the Hg2+ and Cd2+ ion by FA was determined from data of UV-Vis spectra. After treatment, the adsorption capacity of ions by FA increased remarkably in comparison with non-treated FA. The FA treated by NaOH solution has the adsorption capacity higher than FA treated by H2SO4 solution. The maximum adsorption capacity of the FA treated by NaOH solution for Cd2+ and Hg2+ ions at room temperature is 28.97 and 14.60 mg/g, respectively. The equilibrium adsorption data were described by the Langmuir and Freundlich isotherm models. The results showed that equilibrium data were fitted well to the Langmuir isotherm. Keywords. Fly ash, treatment, adsorption capacity, heavy metal, Langmuir isotherm

    EFFECT OF FISH SCALE COLLAGEN ON SOME CHARACTERISTICS AND DRUG RELEASE OF CARRAGEENAN/COLLAGEN/ALLOPURINOL FILM

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    ABSTRACT - QMFS2019Collagen from fish is attracting a lot of attention thanks to its high absorbance ability, biocompatibility as well as non-religious obstruction and cheap sources. It could be applied in many fields, for example: food, cosmetic, or biomedicine. Using of collagen also helps to reduce the environment pollution from fish scale waste in fish processing. In this study, collagen extracted from Vietnamese fresh-water tilapia fish scales was used in combination with carrageenan for the improvement of drug release control. The influence of fish scale collagen content on morphology, thermal behavior and drug release from carrageenan/collagen/allopurinol composite film was evaluated by methods such as field emission scanning electron microscopy (FESEM), differential scanning calorimetric (DSC) and ultraviolet-visible spectroscopy (UV-Vis). From the DSC data, FESEM analysis and drug release of carrageenan/collagen/allopurinol composite films, the most suitable collagen in composite film is 5 wt.%

    EFFECT OF SOME ADDITIVES ON PROCESSBILITY, MECHANICAL PROPERTIES AND MORPHOLOGY OF POLYOXYMETHYLENE/SILICA NANOCOMPOSITES

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    Using additives for polyoxymethylene/silica (POM/SiO2) nanocomposite system is one of suitable solutions to improve processbility, mechanical properties, especially, elongation at break of the material. In this paper, the effect of some additives on the processbility, mechanical properties and morphology of polyoxymethylene/silica (POM/SiO2) nanocomposite was investigated. Zinc stearate (under the commercial name ultraflow – UTF), ethylene-vinyl acetate copolymer (EVA), linear low density polyethylene (LLDPE) and polylactic acid grafted 5 wt.% of polyethylene glycol (PELA) were used as additives for the nanocomposites. The obtained results showed that the preparing process of the POM/SiO2 nanocomposite becam more easily in the presence of PELA, UTF and EVA, corresponding to a lower torque and mixing energy. The PELA caused decrease in the E-modulus or hardness and increase in elongation at break as well as tensile strength of the POM/SiO2 nanocomposites. The SEM images showed that POM and  nanosilica were less compatible in the  nanocomposite using EVA, LLDPE and UTF and they were more compatible with using PELA

    STUDENTS' PERCEPTION OF THE INFLUENCE OF INTONATION IN ENGLISH ON CONVEYING THE MEANING OF SPEECH IN COMMUNICATION

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    In communication, intonation plays an important role in conveying the meaning of a speech. In this article, we study students' perception of the influence of intonation in conveying the meaning of speech in communication to propose solutions to help students overcome intonation errors when communicating, as well as, help teachers have appropriate intonation teaching methods. Our data and analysis are based on research documents, surveys, and in-depth interviews with students. According to the study results, most students are well aware of the importance of intonation and of the factors affecting intonation, and they are also aware of the causes of intonation errors. However, students do not apply their knowledge of intonation to speech, they stop at the cognitive level. The study indicates that students often make intonation mistakes in Tag-question, Wh-question, and Imperative sentence in communication.  Article visualizations

    PREPARATION AND FTIR STUDIES OF PMMA/PVC POLYMER BLENDS, PVC-g-PMMA GRAFT COPOLYMERS AND EVALUATING GRAFT CONTENT

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    This study presents the qualitative and quantitative analyses of Fourier Transform Infrared (FTIR) spectra of poly(methyl methacrylate)/poly(vinyl chloride) blends (PMMA/PVC), as well as PVC-g-PMMA graft copolymers. Graft copolymerizations of methyl mathacrylate (MMA) onto PVC macromolecules were carried out mixture of cyclohexanone/N,N-dimethylformamide as solvents, dibenzoyl peroxide as initiator and nitrogen medium. FTIR spectra of PMMA/PVC blends showed that there were molecular interactions between C=O groups of PMMA and C-Cl groups of PVC. Assignments of infrared absorption bands for specific groups of PMMA/PVC blends have been contributed. Using regression method, linear calibration curve between PMMA mole content and peak areas of C=O groups in FTIR spectra of the blends has been found when C=O peak areas were multiplied by an appropriate factor. PMMA grafted content and total PMMA formed content in PVC-g-PMMA graft copolymers have been evaluated. The results showed that grafted PMMA content was increased since PVC was initiatly dechlorinated by NaOH solution. The grafted PMMA content and total formed PMMA content were 5.05 wt.% and 11.25 wt.% respectively when MMA monomers were grafted onto neat PVC and modified PVC molecules

    Digital capabilities and innovation capabilities in Vietnamese SMEs

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    The objective of the study is to clarify the influence of digital capabilities on innovation capability, considering the direct and indirect impacts of digital leadership and digital culture in small and medium enterprises (SMEs) in Vietnam. The study used a mixed research method including qualitative with in-depth interviews and quantitative with Partial Least Squares Structural Equation Model (PLS-SEM) to analyze 271 responses. Research results show that digital capabilities have a positive impact on SMEs’ innovation capability. Digital leadership and digital culture also, directly and indirectly, affect firms’ digital capabilities and innovation capabilities. From there, the study confirms the theoretical contributions as well as proposes suggestions for SMEs to develop digital capabilities, and as a result, to develop innovation capabilities
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