566 research outputs found

    Process capability indices and X , R control chart limit adjustments by taking into account measurement system errors

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    This paper investigates the effects of measurement system variability arising from evaluations of process capabilities. In this work, relationships between true process capability indices, Cp,True and Cpm,True, and their corresponding observed indices, Cp,Obs and Cpm,Obs, are developed depending on the levels of type I and II errors. Moreover, the method for adjusting control chart limits used to monitor the process is proposed based on measurement system variability. An industrial case study is used to highlight the findings of this investigation and to discuss the adjustment levels that should be conducted depending on the values of type I and type II errors

    Synthesis, spectroscopic, structural and thermal characterizations of [(C7H6NO4)2TeBr6·4H2O]

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    AbstractTellurium (IV) complexes with pyridine-2,6-dicarboxylate ligand were synthesized by slow evaporation from aqueous solutions yielding a new compound: [(C7H6NO4)2TeBr6·4H2O]. The structure of this compound was solved and refined by single-crystal X-ray diffraction. The compound is centrosymmetric P21/c (N°: 14) with the parameters a=8.875(5)Å, b=15.174(5)Å, c=10.199(5)Å, β=94.271° (5) and Z=2. The structure consists of isolated H2O, isolated [TeBr6]2− octahedral anions and (pyridine-2,6-dicarboxylate) [C7H6NO4]+ cations. The stability of the structure was ensured by ionic and hydrogen bonding contacts (N–H⋯Br and O–H⋯Br) and Van-Der Walls interaction. The thermal decomposition of the compound was studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The FTIR and Raman spectroscopy at different temperatures confirm the existence of vibrational modes that correspond to the organic, inorganic and water molecular groups. Additionally, the UV–Vis diffuse reflectance spectrum was recorded in order to investigate the band gap nature. The measurements show that this compound exhibits a semiconducting behavior with an optical band gap of 2.66eV

    When Users Enjoy Using the System: The Case of AIS

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    This study utilized an extended model of the Unified Theory of Acceptance and Use of Technology (UTAUT2) to explore the factors influencing the future adoption of accounting information systems (AIS) by Qatari students. A research model was proposed to predict future adoption, partially moderated by voluntary status of using the system. A sample of 237 students was used to probe their perceptions regarding the use of such systems in their future careers. Students were enrolled in an accounting information systems course in Qatar University. Results indicated that perceived facilitating conditions, performance expectancy and enjoyment were significant predictors of AIS. The other factors failed to be significant predictors. The estimated R2 was 48.4%. The moderation effect of voluntariness was also significant in influencing the relationship between enjoyment and future adoption. The moderator yielded a negative beta, which means that it faded the relationship under consideration. Conclusions and future recommendations are reported at the end of the paper
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