This paper presents the roll-coating analysis of couple stress fluid under lubrication approximation theory. The governing differential equation developed under the approximation is solved to get exact expressions for velocity and pressure gradient. The engineering quantities of interest such as pressure, roll-separating (load-carrying) force, and power input function are computed numerically. How the couple stress fluid material parameter affects velocity, pressure, pressure gradient, load-carrying force, and power input is shown graphically. One observes that couple stress model predicts higher pressure in the nip region when compared to the Newtonian model. The load-carrying force and power input exceed their Newtonian values for strong couple stress effects. Moreover, the separation point moves left of its Newtonian value with increasing couple stress effects.

The non-isothermal flow inside a calender is modeled and analyzed for a couple stress fluid. The governing flow equations are developed using conservation laws of mass, momentum and energy. An order of magnitude analysis is performed and leading terms in momentum and energy equations are retained. The reduced momentum equation is solved to obtain the exact expression for velocity and pressure gradient. The reduced energy equation is solved numerically using a hybrid numerical method. The significant effects of the involved parameters on the pressure, pressure gradient velocity profile, roll-separating force, power input, exiting sheet thickness and temperature are examined through various plots. The pressure inside the calender significantly increases with increased couple stress effects. For larger couple stress parameters, the power function and roll-separating function show steady state behavior. The two maxima are distinctly observed in temperature distribution near the roll surfaces for small couple stress effects c ! 1 ð Þ. In contrast, the temperature achieves maximum at center for strong couple stress effects c ! 0 ð Þ:

Sugarcane (Saccharum officinarum) is one of the major crops cultivated in tropical and sub-tropical countries, and the primary purpose is to obtain raw sugar. It is an important substance for sugar and alcohol production by both the sugar and beverage industries. During cane processing, various byproducts are obtained, namely sugarcane bagasse, bagasse ash, pressmud cake, sugarcane vinasse, and spent wash. There are many challenging problems in storage, and they cause great environmental pollution. This review discusses their properties by which they can be used for cleaner agricultural and environmental sustainability. Utilization of byproducts results in value-added soil properties and crop yield. Replacing chemical fertilization with these organic natured byproducts not only minimizes the surplus usage of chemical fertilizers but is also cost-effective and an eco-friendly approach. The drawbacks of the long-term application of these byproducts in the agricultural ecosystem are not well documented. We conclude that the agriculture sector can dispose of sugar industry byproducts, but proper systematic disposal is needed. The need arises to arrange some seminars, meetings, and training to make the farming community aware of byproducts utilization and setting a friendly relationship between the farming community and industrialists.

Abstract We investigate the effects of non-Newtonian parameters on the exiting sheet thickness in the calendering of Oldroyd 4-constant fluid. The governing equations are first converted into dimensionless form and then simplified under lubrication approximation theory. A complete numerical approach is developed based on Matlab built-in routine “bvp4c” in order to obtain stream function and pressure gradient. The pressure is computed using Runge-Kutta method. The effects of involved material parameters on various quantities of interest are highlighted through graphs. The results indicate that Oldroyd 4-constant model predicts lower pressure in the nip region than that of the Newtonian model. The force and power for Oldroyd 4-constant model are also lower than their counterparts for Newtonian model. Moreover, the leave-off distance is nearly independent of the material parameters of the Oldroyd 4-constant model for larger value of the entering sheet thickness.

A theoretical analysis based on the lubrication theory is presented to study the calendering mechanism. The material to be calendered is described by the constitutive relationship of a micropolar fluid. An exact solution and numerical solution of the problem is calculated. The roll‐separating force, power function and exiting sheet thickness are computed numerically using Runge‐Kutta method. The influence of the material parameters on the pressure distribution, pressure gradient and related quantities of engineering interest in calendering process is analyzed through graphs. POLYM. ENG. SCI., 58:327–334, 2018. © 2017 Society of Plastics Engineers