Mineral wool melt fiberization on a spinner wheel

In this paper, the formation of mineral wool fibres has been studied on a real industrial production process. Parametric dependence of the melt film structural dynamics on the spinner wheel rotational frequency was investigated. The results presented indicate the presence of the melt instability that is formed as a complex quasi-periodic oscillation of the structures on the melt film surface. In addition to the melt oscillations which coincide with the rotating frequency of the spinner wheel and its higher harmonics, aperiodic melt structures also appear. These structures result from the Taylor instability, which is inherent to liquid movement and is one of the basic mechanisms of the formation of melt ligaments that solidify into mineral wool fibres. Based on the results, a phenomenological model for structural instability as a function of the wheel rotational frequency was formed, indicating a characteristic influence of melt film dynamics on the fibre formation and indirectly, on the quality of the end product.     

Application of Taguchi method to investigate the effects of process factors on the performance of batch emulsion polymerization of vinyl chloride

In this article, the influences of five operating variables on the molecular weight (or K‐value), polydispersity index (PDI), as well as polymerization yield of emulsion poly (vinyl chloride) in batch reactor were investigated simultaneously using Taguchi experimental design approach. The variables were temperature (T), water to monomer weight ratio (r), concentrations of initiator ([I]) and emulsifier ([E]), and agitation speed (S). Statistical analysis of results revealed the significance order of factors affecting the product qualities and quantity. It was found that the reaction temperature is the principal operating factor to control the molecular weight, and this is attributed to promotion of chain transfer reactions to monomer in this system. The effect of this factor on PDI is also comprehensively discussed. The significance sequences of important factors on yield are: S > [E] > r. The polymerization yield increases with S and [E] but decreases as r is increased. The relative optimum condition for a typical paste application was also determined using overall evaluation criteria. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Cyclic pressure applied to cows' teats by teatcup liners can be determined simply and noninvasively

Liner overpressure is a quantitative variable indicating the extent to which the vacuum difference across the liner during phase d (the liner compression phase) of milking machine pulsation exceeds the vacuum difference that would be just sufficient to stop milk flow from the teat. Previously defined methods of determining liner overpressure have required modifications to the milking machine, complex instrumentation, or both. Our method of measuring derived overpressure (OP) offers relatively simple instrumentation and realistic milking machine characteristics. We determined derived OP by measuring the duration of milk flow within a pulsation cycle, and then comparing that duration with the shape of the pulsation curve to deduce the pulsation chamber vacuum level corresponding to that duration. Derived OP by our method yielded measurements of OP that differed by less than 2.0 kPa from those determined by the most practical previous method, for 2 trial liners. Derived OP can serve as a method for comparing and evaluating liners, and the method we developed may also be applied to automatic control of the milking process.     

Transient analysis of coupled non‐uniform transmission line using finite element method

This paper presents a finite element time domain model for a numerical solution of a coupled non‐uniform transmission line problem. On the basis of the finite element method, a novel numerical procedure for the solution of a system of the non‐uniform multi‐conductor transmission line equations in the time domain is presented. The results obtained by the proposed method have been compared with the solution obtained using the finite difference time domain method, and an excellent correlation has been demonstrated. Copyright © 2014 John Wiley & Sons, Ltd.     

Experimental characterization and modeling of dry clutch wear with emphasis on fading effect

Forschung im Ingenieurwesen - The paper presents results of experimental characterization and modeling of dry clutch material wear, which concerns four input parameters (temperature, slip speed,...     

Thermochemical Conversion of Black Liquor in the Liquid Phase

Abstract

Black liquor from kraft pulping of pine wood was pressure heated (about 20 MPa) for 45 minutes at both 300 °c and 350 °c and in both the presence and absence of a reducing atmosphere. Variable amounts of organic-phase (40–64 % of the black liquor organics), water-soluble (14–70 %), and volatile (12–55 %) products were formed. The organic-phase product originates mainly from the lignin fraction of black liquor, whereas, during the treatments, the corresponding hydroxy acid fraction was primarily degraded into lower acid intermediates and volatile components. The effects of temperature and gas atmosphere (carbon monoxide, hydrogen or nitrogen) on the conversion of black liquor are discussed.