Mechanism of secondary gel-particle formation in viscose

Conclusions Experimental and calculated data have been given which support the mechanism for formation of secondary gel particles in viscose.According to this mechanism, the formation of gel particles takes place in the case where the time for diffusion exchange between the main stream and an immobile wall layer is greater than the time for coagulation.VNIIPV, Mytishchi. Translated from Khimicheskie Volokna, No. 2, pp. 22–24, March–April, 1992.     

In-field comparison among polarization-mode-dispersion measurementtechniques

We report polarization mode dispersion measurements on a 168 km long undersea optical cable, performed with two techniques. From experimental results, statistical behavior of polarization parameters and their time fluctuations have been extracted. An average differential group delay of about 13 ps shows that dispersion-shifted fibers can be affected by a polarization dispersion significantly larger than standard step-index fibers. The correlation length of the polarization-coupling perturbation in the tested fibers is not negligible with respect to the link length     

A theoretical design basis for minimizing CMOS fixed taper bufferarea

This paper develops a theoretical basis for the minimization of chip area required for fixed taper buffer design. It modifies the well-known procedure for minimizing delay time in such circuits to derive a minimum number of required stages. Rather than minimize delay time, the procedure realizes a specified buffer delay time using a stage-area scale factor that minimizes the total area of the buffer. Since an integer number of tapered stages must be used while the calculations lead to noninteger results, the effects of roundoff errors are included     

Cortical implants for the blind

Arrays of stimulating electrodes can be placed in the brain itself, in the visual cortex, to bring vision to the profoundly blind. However, when designing such devices one needs to take into consideration the fact that the visual pathway maps images onto cortical structures in a complex and unpredictable way     

Finite twist and extension of a cylindrical elastic membrane

Summary We consider a circular cylindrical membrane subjected to longitudinal extension and twist. The associated equilibrium deformation is considered to be axisymmetric and the analysis is based on a direct two-dimensional formulation. Wrinkling of the membrane is taken into account in an approximate way by introducing arelaxed strain energy function derived from the neo-Hookean strain energy for isotropic elastic solids. Analytical formulae for wrinkled parts of the membrane are used to corroborate the results of a numerical treatment of the full boundary value problem.Dedicated to the memory of A. C. Pipkin     

Direct algorithms for data analysis in the location of sources of radiation from measured differences in distance: Model experiment

Results are presented from a model (numerical) experiment performed to check the efficiency of three groups of direct data-analysis algorithms to be used in satellite location of ground or ocean sources of radiation. The methodology behind the experiment is also explained. Translated from Izmeritel'naya Tekhnika, No. 12, pp. 40–44, December, 1996.     

Evaluation of a Conical Mill for Screening of Direct Compression Formulations

Suitability of a Quadro Comil^TM for screening of direct compression tablet masses was evaluated with respect to alteration of particle size distribution and blending efficiency. Air jet sieving was qualijied for determination of a particle size of spraydried lactose and microcrystalline cellulose. Using a full 3¹ × 2³ factorial design not only effects of single processing parameters (output screen size, impeller shape, velocity of the mill, and type of powder), but also their respective combinations were investigated in terms of impact on particle size and flow properties (angle of repose, bulk and tapped densities). Particle sizes before and after passing the Comil were found to be normally distributed. The results indicate that the process does not allow any of the powder characteristics studied beyond normal batch-to batch variability. This refers in particular to the proportion of fines. For evaluation of the deagglomeration effectiveness, a 2³ design was implemented with iron oxide as a model drug. Homogeneity of the blends was determined optically, and after screening twice it was found to be acceptable even with this substance, which has a particularly high agglomeration tendency, high density, and small particle size. The Quadro Comil is therefore regarded as fully suitable for deagglomeration of powders in a gentle and effective manner     

Ascitic fluid analysis in hepatocellular carcinoma

BACKGROUND: Ascites in patients with hepatocellular carcinoma (HCC) is a poorly characterized subgroup of malignancy-related ascites. Not only the underlying liver disease, but also the tumor growth and spread contributes to the ascites formation. The authors differentiated ascites in HCC from other types of ascites. METHODS: The authors analyzed the ascitic fluid of 185 consecutive patients (89 liver cirrhosis, 33 HCC, 31 peritoneal carcinomatosis, 22 liver metastases, 10 spontaneous bacterial peritonitis). RESULTS: Each subgroup showed a typical pattern. Compared with the cirrhotic patients, those with HCC showed a higher frequency of positive cytologic findings (4 of 33 versus 0/89, P < 0.004), elevated fibronectin concentration (10/33 versus 8/89, P < 0.004), and elevated polymorphonuclear cell count (10/33 versus 5/89 P < 0.004). CONCLUSIONS: A significant number of patients with ascites and HCC patients showed signs of peritoneal infiltration with positive cytologic findings and increased concentration of fibronectin. Moreover, neutrocytic ascites without signs of superinfection is relatively common (30%).