Dynamic behaviour of dyeing machinery and computer simulation — some examples

A summary of two studies of different types of well-known dyeing machinery is presented. Logical analysis and experimental studies of fluid flow in wet textile processes give a clear understanding of machine operation. This fundamental information combined with present knowledge of dye-fibre chemistry then allows the operation and control to be simulated in ways not previously possible.     

Stress-strain characteristics of particulate material under the condition of no lateral strain

This paper deals with an application of generalized non-linear stress-strain relationships of an incremental nature for a particulate material in order to investigate the behaviour of a bed subjected to a loading cycle during which lateral strain is prevented. Initially, the limiting conditions in a bed of granular material are discussed, and a brief review presented of relevant work already carried out under the condition of no lateral strain. Both normally consolidated, and over-consolidated, beds are considered. The resulting calculations indicate that the stress history of the bed can have, depending on stress levels, a profound effect on behaviour during subsequent reloading. Both the state of stress and the stress-strain behaviour of the deposit are assessed. Finally, the results are shown to have an important application in a number of engineering problems, particularly where overconsolidated beds of material are under consideration.List of symbols K ₀ coefficient of earth pressure at rest. - K _r Rankine ratio=(1–sin)/(1+sin) - K ₁,K ₂,f ₁,f ₂,g constants found experimentally - p _h stress in any horizontal direction whenP _x =P _z =P _h - p _x. stress in co-ordinate directions - P _xi,P _yi,P _zi stress levels in co-ordinate directions at commencement of unloading/reloadcycle - r ₁,r ₂,r ₃ stress ratios=p _x (ultimate)/p _xi ,p _y (ultimate)/P _yi ,p _z (ultimate)/P _zi respectively - P _y , _y , etc a small increment of the quantity concerned - _x . strains in co-ordinate directions - angle of internal friction of soil     

Entrainment of air into liquids by a high speed continuous solid surface

The paper reports a wide range of experimental data on air entrainment velocities and apparent dynamic contact angles, were a continuous surface entersThe main dimensional correlation took the form:

for variables in the range:

However, due to the limited range of fluid densities used (0.785-1.26 * 10³kg.m³), a simpler correlation for air entrainment velocity was found

for the case of the entrainment of air by a plunging solid surface where 0.2 <(ηs/η9u)>< 3.2m.sec^-1 was found to be the corresponding rThe critical capillary number Ca_c was found to lie in the range 0.2 <Ca_c< 1.26 which agrees very well with a recent study due to GuThe investigation also showed that anomalous behaviour could occur with charged surfaces or surfaces with significant roughness. Surfactant type was al     

Mass-transfer Processes in Hank-dyeing Machines II—Operational and Design Implications of the Experimental Study

Meeting of the Midlands Region, held at the Carpet Trades Ltd Canteen, Kidderminster, on 13 February 1969, Mr D. O. Douglas in the chair Simulation of dyeing processes on an analogue computer, using techniques described in Part I of this paper (p. 187), has been employed to establish the minimum flow requirements for practical machines using dyes differing in dyeing behaviour. A limiting rate of flow requires to be achieved to eliminate differences in colour between hanks in practical machines. The failure to meet this condition is responsible for much of the problem of achieving level dyeings.     

Soil Based Vegetation Productivity Model for the North Dakota Coal Mining Region

In our study, we addressed the development of an agricultural productivity equation within a landscape context for the North Dakota coal fields in Oliver, Mercer, and Dunn counties. The procedure employed principal component analysis to develop a combined vegetation yield variable from spring wheat (Triticum aestivum L.), barley (Hordeum vulgare L), oat (Avena sativa L.), grass/legume, Eastern red cedar (Juniperus virginiana L.), ponderosa pine (Pinus ponderosa var. scopulorum Engelm.), green ash (Fraxinus pennsylvanica Marsh.), Siberian peashrub (Caragana arborescens Lam.), American plum (Prunus americana Marsh.), and common chokecherry (Prunus virginiana L.). The best equation we developed to predict plant growth in the surface mining portion of the study area contained an R 2 = 0.66 and an overall p-value of 0.0001. The regression coefficients were stable under bootstrap and jackknife evaluation procedures and worked relatively well with a subsampling procedure. The equation correlated (0.7301) with reclaimed soil field trials.     

The effect of laser chirping on lightwave system performance

Directly modulated semiconductor lasers exhibit a dynamic wavelength shift (chirping) arising from gain-induced variations of the laser refractive index. The effect of laser chirping on the performance of multi-Gb/s lightwave systems operating at a wavelength of 1550 nm is investigated. Models suitable for computer-aided analysis are used to describe the dynamic response of the laser and the propagation of chirped optical pulses through a step-index single-mode optical fibre. A truncated pulse train, Gauss quadrature rule method is used to evaluate the average bit error rate of the receiver. This permits pattern effects in the transmitted optical waveform due to the laser dynamics and nonlinear optical power transmission properties of optical fibers to be included in the system model. The influence that modulation and device parameters have on the receiver sensitivity is assessed     

Vector representation and analysis of areally distributed variables

When areally distributed variables are represented by vectors relative to a single reference point location, resultant vectors (distribution vectors) can be used to measure the geographic distribution of the variables simultaneously taking into account (1) thevalues of the variables, (2) thedirection, relative to the reference location, of the points at which the values are located, and (3) thedistances between the reference point and the data points. The distribution vector method provides measures of weighted mean location (distribution mean location) and dispersion (standard distance) that reflect the value direction, and distance of variables relative to the reference location. The distribution vector method has versatile applicability to problems involving areally distributed variables and can be used with other quantitative methods. An illustrative application of the distribution vector method with a statistical spatial interaction model of airline passenger traffic from St. Louis to 27 selected SMSAs for each year from 1960 through 1965 is included.I wish to thank my colleagues Prem S. Laumas and Eldon Reiling as well as Gerhard Tintner, Laurence Jay Mauer and Stanley Johnson, for their comments and suggestions on an earlier version of this paper.     

Re‐Calibration of the UK Large Scale Gap Test

A new donor explosive, ROWANEX 3601 has been selected for use in the large scale gap test (LSGT). It was necessary to calibrate the peak pressure recorded on the central axis of the PMMA gap using calibrated piezo‐resistive pressure transducers as a function of the gap thickness. The stress history within the PMMA gap was measured and the peak pressure plotted against gap thickness as a calibration. Further effects were noted relating to the curvature of front exiting the donor charge and the validity of the measurement of the transmitted shock at small gap thicknesses.