Micropolar fluid flow with temperature‐dependent transport properties

In the present article, the heat transfer rate and the fluid flow of a micropolar fluid along with temperature‐dependent transport properties are scrutinized in the presence of heat generation. The variability in transport properties leads to a rise in the heat transfer and decreases the skin friction. Furthermore, Fourier's heat flux model is implemented in the analysis of heat transfer, employing a suitable transformation to convert the flow model into nonlinear ordinary differential equations. Numerical solutions are obtained by using the shooting method/bvp4c technique. Physical quantities of interest, such as local skin friction and Nusselt number, are discussed and computed. Skin friction decreases with the micropolar parameter but the Nusselt number shows the opposite behavior for the micropolar parameter.     

Co‐poly(vinyl chloride‐vinyl acetate‐vinyl alcohol)‐silica nanocomposites from sol–gel process: Morphological,mechanical, and thermal investigations

Organic–inorganic nanocomposites consisting of co‐poly(vinyl chloride‐vinyl acetate‐vinyl alcohol) and silica were prepared via sol–gel process. Two types of hybrids were prepared, one in which interactions between hydroxyl group present in the copolymer chain and silanol groups of silica network were developed. In the second set, extensive chemical bonding between the phases was achieved through the reaction of hydroxyl groups on the copolymer chains with 3‐isocyanatopropyltriethoxysilane (ICTS). Hydrolysis and condensation of tetraethoxysilane and pendant ethoxy groups on the chain yielded inorganic network structure. Mechanical and thermal behaviors of the hybrid films were studied. Increase in Young's modulus, tensile strength, and toughness was observed up to 2.5 wt % silica content relative to the neat copolymer. The system in which ICTS was employed as binding agent, the tensile strength and toughness of hybrid films increased significantly as compared to the pure copolymer. Thermogravimetric analysis showed that these nanocomposite materials were stable up to 250°C. The glass transition temperature increases up to 2.5 wt % addition of silica in both the systems. Field emission scanning electron microscope results revealed uniform distribution of silica in the copolymer matrix. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Physicochemical and Antioxidant Characteristics of Kapok (Ceiba pentandra Gaertn.) Seed Oil

In view of the growing demand for vegetable oils and fats, currently exploration of some under-utilized and non-conventional oil seed crops is of great concern. This work presents data on the detailed physicochemical and antioxidant attributes of kapok (Ceiba pentandra Gaertn.) seed oil. The kapok seeds contained an appreciable amount of oil (27.5 %), protein (35.0 %) and fiber (19.0 %). The extracted kapok seed oil (KSO) had an iodine value of 101.8 g of I₂/100 g of oil, a saponification value of 187 mg of KOH/g of oil), and unsaponifiable matter 0.83 %. KSO also showed a good oxidation state as indicated by the measurements of the peroxide value, conjugated dienes, conjugated trienes, para-anisidine and the induction period (Rancimat method). The tested oil showed a considerable amount of total phenolics (2.50 mg/100 g) and an appreciable free radical scavenging capacity. Gas liquid chromatographic analysis of fatty acids (FA) reveals that KSO mainly has linoleic acid (33.6 %) followed by oleic acid (23.4 %) and palmitic acid (22.4 %). Besides, a notable amount of cyclopropenoid fatty acids such as malvalic acid (9.1 %) and sterculic acid (2.8 %) was also detected. The FA composition of the tested oil was further verified by recording FTIR and NMR spectra. Among the oil phytosterols, analyzed by GC/GC–MS, β-sitosterol was found to be the principal component whereas RP-HPLC analysis showed the occurrence of γ-tocopherol (550 mg/kg) as the major tocopherol along with considerable amount of α-tocopherol (91 mg/kg) and δ-tocopherol (5.52 mg/kg). It can be concluded from the results of this comprehensive study that under-utilized kapok seeds are a potential feed stock for the production of a useful oil for edible and/or oleochemical applications.     

A state-based approach to integration testing based on UML models

Correct functioning of object-oriented software depends upon the successful integration of classes. While individual classes may function correctly, several new faults can arise when these classes are integrated together. In this paper, we present a technique to enhance testing of interactions among modal classes. The technique combines UML collaboration diagrams and statecharts to automatically generate an intermediate test model, called SCOTEM (State COllaboration TEst Model). The SCOTEM is then used to generate valid test paths. We also define various coverage criteria to generate test paths from the SCOTEM model. In order to assess our technique, we have developed a tool and applied it to a case study to investigate its fault detection capability. The results show that the proposed technique effectively detects all the seeded integration faults when complying with the most demanding adequacy criterion and still achieves reasonably good results for less expensive adequacy criteria.     

Step-zoom dual-field-of-view infrared telescope

The design of a dual-field-of-view telescope for an 8-12-microm imaging waveband is described. Preliminary calculations are made to determine the first-order parameters of the narrow- and the wide-field modes. To achieve a switchable dual-field-of-view system, one use an optical configuration based on the axial motion of a single lens group along the optical axis. The same lens is also used for focusing at near objects and for athermalization by small axial movement. A total of six lenses with one conic surface are used in the design, making the telescope cost effective and lightweight. The final optical design is presented, along with the aberrations curves and modulation transfer function plots, showing excellent performance in both fields of view.     

Numerical Analysis of Peristaltic Transport of a Tangent Hyperbolic Fluid in an Endoscope

This paper presents a tangent hyperbolic fluid in a cylindrical coordinate system. The governing equations are simplified using long-wavelength and low Reynolds number approximations. The solutions of the problem in simplified form are calculated with three methods: (1)?perturbation method, (2)?homotopy analysis method, and (3)?shooting method. Comparison of the three solutions shows very good agreement among them. Pressure rise and frictional force are calculated with the help of numerical integration. Graphical results for pressure rise and frictional forces are presented to show the physical behavior of the Weissenberg number We, amplitude ratio ?, tangent hyperbolic power law index n, and radius ratio ?.