Structure and Dynamics in Polyacrylami de Hydrogels With and Without Probe Particles : A Light Scattering Study

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Identification of bottlenecks to improve equipment availability: a case study

In this highly competitive market where the demand for the products is increasing gradually, it is essential for a manufacturing company to reduce the production cycle time and cost accordingly. One of the methods for this is to increase the availability of process. This paper attempts to identify and quantify the causes of machine downtime in a manufacturing company. For this a four-prong approach is taken: Firstly, the major causes for the low availability of process are determined, where bearing failure is found to be the major causes of low availability. Second, combining desirability function approach and data envelopment analysis are performed to identify the sensitive input variables that affect the bearing failure. Thirdly, ordinary linear regression is used to validate the results of DEA. Lastly, some managerial implications to reduce the downtime were suggested. We have considered an electrolytic tinplating line process in a tin sheet manufacturing company as a case study.data envelopment analysis; DEA; linear regression; machine availability; machine downtime; desirability function; bottleneck identification; bottlenecks; manufacturing equipment; bearing failure; electrolytic tinplating; tin sheet manufacturing.

Coupled Ion Conduction Mechanism and Dielectric Relaxation Phenomenon in PEO₂₀–LiCF₃SO₃‑Based Ion Conducting Polymer Nanocomposite Electrolytes

This study focuses on the effect of anatase titania acting as nanofiller on the relaxation dynamics and ionic conductivity behavior in polymer nanocomposite electrolyte based on PEO₂₀–LiCF₃SO₃–TiO₂. Using broadband dielectric spectroscopy, the dynamics of ion transport mechanism is studied over a wide range of temperature and frequency. Polymer salt complex exhibit the direct current (dc) conductivity σ_dc = 3.760 × 10^–7 S cm^–1 at 303 K. But with the addition of 8 wt % TiO₂, a 2-order increase in the magnitude of dc conductivity is observed at the same temperature. Ion conduction mechanism is analyzed employing a complex relative permittivity as well as modulus formalisms. Isotherms of real part of conductivity spectra and dielectric loss spectra are analyzed to explain the observed first and second universalities in the ion conduction mechanism. Kramer–Krönig approach is used to discuss the crossover between the two universalities. Ratner’s classical approach in combination with modified Nernst–Einstein relation is used to correlate the coupling nature of polymer segmental relaxation and ionic transport mechanism. Successful scaling of conductivity spectra using the Summerfield approach and imaginary modulus spectra using maxima normalization approach indicate that ionic transport mechanism is a thermally activated temperature-independent phenomenon. Temperature-dependent dc conductivity is explained using a mismatch-generated relaxation for the accommodation and transport of ions concept as well as Vogel–Tammann–Fulcher relation to get a better insight into the ion conduction mechanism. With a comprehensive study of the relaxation events and ionic conductivity, a close coupling between polymer segmental relaxation and ionic conduction in polymer nanocomposite electrolytes is observed

Dynamics of Deinococcus radiodurans under Controlled Growth Conditions

Deinococcus radiodurans is a potent radiation resistant bacterium with immense potential in nuclear waste treatment. In this investigation, the translational and rotational dynamics of dilute suspensions of D. radiodurans cultured under controlled growth conditions was studied by the polarized and depolarized dynamic light-scattering (DLS) techniques. Additionally, confocal laser scanning microscopy was used for characterizing the cultured samples and also for identification of D. radiodurans dimer, tetramer, and multimer morphologies. The data obtained showed translational diffusion coefficients (D(T)) of 1.2 × 10(−9), 1.97 × 10(−9), and 2.12 × 10(−9) cm(2) /s, corresponding to an average size of 3.61, 2.22, and 2.06 μm, respectively, for live multimer, tetramer, and dimer forms of D. radiodurans. Depolarized DLS experiments showed very slow rotational diffusion coefficients (D(R)) of 0.182/s for dimer and 0.098/s for tetramer morphologies. No measurable rotational diffusion was observed for multimer form. Polarized DLS measurements on live D. radiodurans confirmed that the bacterium is nonmotile in nature. The dynamics of the dead dimer and tetramer D. radiodurans were also studied using polarized and depolarized DLS experiments and compared with the dynamics of live species. The dead cells were slightly smaller in size when compared to the live cells. However, no additional information could be obtained for dead cells from the polarized and depolarized dynamic light-scattering studies