Nonsimilar solution of a boundary layer flow of a Reiner–Philippoff fluid with nonlinear thermal convection

The thermodynamics modeling of a Reiner–Philippoff-type fluid is essential because it is a complex fluid with three distinct probable modifications. This fluid model can be modified to describe a shear-thinning, Newtonian, or shear-thickening fluid under varied viscoelastic conditions. This study constructs a mathematical model that describes a boundary layer flow of a Reiner–Philippoff fluid with nonlinear radiative heat flux and temperature- and concentration-induced buoyancy force. The dynamical model follows the usual conservation laws and is reduced through a nonsimilar group of transformations. The resulting equations are solved using a spectral-based local linearization method, and the accuracy of the numerical results is validated through the grid dependence and convergence tests. Detailed analyses of the effects of specific thermophysical parameters are presented through tables and graphs. The study reveals, among other results, that the buoyancy force, solute and thermal expansion coefficients, and thermal radiation increase the overall wall drag, heat, and mass fluxes. Furthermore, the study shows that amplifying the space and temperature-dependent heat source parameters allows fluid particles to lose their cohesive force and, consequently, maximize flow and heat transfer.     

High-resolution lidar-based landslide hazard mapping and modeling,UCSF Parnassus Campus,San Francisco,USA

Airborne lidar (light detection and ranging) was used to create a high-resolution digital elevation model (DEM) and produce landslide hazard maps of the University of California, San Francisco Parnassus Campus. The lidar DEM consisted of nearly 2.8 million interpolated elevation values covering approximately100 ha and posted on an 0.6 m horizontal grid, from which a set of 16 maps was produced. The first subset of maps showed aspects of the topography useful for landslide mapping, an engineering geological map and a qualitative slope hazard map. The second subset consisted of physics-based probabilistic landslide hazard maps for wet static, wet seismic, and dry seismic conditions. This case history illustrates the utility of lidar-based products, supplemented by field-based geological observations and physics-based probabilistic slope stability modeling, for the evaluation of existing and potential slope stability hazards on a steep and heavily forested site.      

Grafting of acrylonitrile onto allylated caesarweed fibers by potassium permanganate – N,N′‐dimethylacetamide redox pair

Caesarweed fiber, Urena lobata, was modified by successive treatment with sodium hydroxide and allylchloride in diethylether to yield an average degree of substitution of 2.73 allyl moieties per anhydroglucose unit. The presence of allyl moieties on the fiber was confirmed by infrared spectroscopy. Graft copolymerization of acrylonitrile onto the unmodified and allyl‐modified fibers was initiated by potassium permanganate –N,N′‐dimethylacetamide redox pair in aqueous medium. The allyl fiber was markedly less reactive than the unmodified fiber with graft yields for the latter a factor of 2.3 higher than those of the former. This was attributed to resonance stabilization of allylic macroradicals of the fiber. The graft yield showed positive dependence on N,N′‐dimethylacetamide concentration in the range, 9.0–45.0 × 10^?4M with P_g/P_go of up to 1.39 at the highest concentration. The conversion in graft yield was however characterized by a plateau at the latter concentration and was ascribed to termination of grafted polymer chains by methylacetylaminomethyl radical initiating species. Spectroscopic evidence in support of the latter was the absorption peak at 1680 cm^?1 for the graft copolymers, characteristic of C?O stretching vibration for tertiary amide. Acetic acid, at concentrations in the range 0.28–2.22M, was inimical to grafting of acrylonitrile onto allylfibre with P_g/P_go, of less than one. Grafting onto allylfiber showed positive temperature dependence in the range, 30–50°C with calculated activation energy of 12.3 kcal mol^?1 for the graft polymerization reaction. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effects of temperature and moisture on the anaerobic digestion of refuse

The influence of the first-tier variable temperature on the anaerobic decomposition of refuse was investigated by use of laboratory models. Temperature was found to exert significant effects on the interrelated metabolic processes of acidogenesis, solventogenesis and methanogenesis. A temperature elevation from a mean ambient regime (18.7°C) to 30°C resulted in a 2.6-fold increase in the methanogenic rate while a 7.8-fold increase was observed when the temperature was raised from 18.7 to 40°C. The rate of methanogenesis at 40°C was approximately three-fold higher than at 30°C. Further temperature elevation to 55°C, however, resulted in the cessation of methanogenesis although solventogenesis was promoted. An attempt was made to extrapolate the results obtained to actual landfill, with specific reference to the role of refuse density in thermogenesis.     

Sodium bicarbonate effects on the anaerobic digestion of refuse

Laboratory column and bottle cultures were used to examine the efficacy of NaHCO₃ additions (1%, 2.5% and 5% w/v) to promote the solid-state refuse fermentation. Buffering capacity increase, by addition of 2.5% NaHCO₃, equivalent to 84 mg NaHCO₃ g dry weight refuse_-1, promoted both acidogenesis and methanogenesis, with the latter accelerating by a factor of six, compared with glass-distilled water controls. Increased addition, with 5% NaHCO₃, however, mediated partial suppression of methanogenesis and acidogenesis with cation toxicity the most likely cause. Promotion of the refuse fermentation by NaHCO₃ addition, therefore, necessitates careful control of the concentration applied.     

Methine dyes formed by condensation of indane-1, 3-dione and cyanovinyl analogues with benzaldehydes

A range of dyes has been synthesised by condensing highly electronegative active methylene compounds derived from indane-1, 3-dione with the formyl group of substituted benzaldehydes. The visible absorption spectroscopic properties of the dyes were investigated. In general the dyes provided bright colours, ranging from yellow to blue on synthetic fibres when applied by vapour-phase transfer printing, the prints having reasonable fastness to washing (ISO 3).     

Operational enhancements for small scale thermal energy storage devices

Microsystem Technologies - Thermal energy storage (TES) has been a significant contributor to energy efficiency and solar energy sources on the macro-scale for decades. Recently, there has been...     

Fixation characteristics of carboxylated dyes on polyamide fibres

Reactions of dyes, some of which contain a carboxylic acid group, on polyamide have been investigated using nine different dyes of differing chemical structures. Fixation characteristics and dye–fibre bond stability to alkaline washing were also studied. Light fastness and ability to cover barre effects on nylon were investigated. Studies were also made on the effect of carbodiimide on fixation and dye–fibre bond stability of these dyes on nylon fibres.     

Object Tracking-Based “Follow-Me” Unmanned Aerial Vehicle (UAV) System

The applications of information technology (IT) tools and techniques have, over the years, simplified complex problem solving procedures. But the power of automation is inhibited by the technicality in manning advanced equipment. To this end, tools deliberately combating this inhibition and advancing technological growth are the Unmanned Aerial Vehicles (UAVs). UAVs are rapidly taking over major industries such as logistics, security, and cinematography. Among others, this is a very efficient way of carrying out missions unconventional to humans. An application area of this technology is the local film industry which is not producing quality movies primarily due to the lack of technical know-how in utilizing these systems. This study therefore aim to devise an autonomous object tracking UAV system that would eliminate the complex procedure involved in stabilizing an aerial camera (aerial bot) midair and promote the creation of quality aerial video shooting. The study adopted Unified Modeling Language (UML) tools in modeling the system’s functionality. The traditional Server-Client model architecture was adopted. The OpenCV library employed proved highly efficient in aiding the tracking procedure. The system provided a usable web controller which provides easy interaction between the pilot and the drone. Conclusively, investments in UAVs would enhance creation of quality graphic contents.