Thermal Properties of Pineapple Leaf Composite and its Suitability as a Viable Alternative for Efficient Roofing Material

For self-cooling building designs, the thermal properties of pineapple (Ananas Comosus) stalk composite were investigated and compared with those of asbestos with a view to establishing its suitability as ceiling material. Sample boards from pineapple leaves were prepared by drying and grinding, then forming them into boards without an external binder. The major parameter, thermal conductivity К was determined using Lee’s Disc apparatus. Other parameters determined were specific heat capacity c, density ρ, thermal resistivity ρth, thermal diffusivity λ, and thermal absorptivity α, were determined by using the appropriate experimental methods or calculations. The thermal conductivity of Ananas Comosus was determined to be 0.0719±0.0007Wm-1K-1. Using the same Lee’s Disc apparatus method, the thermal conductivity of the commercial asbestos ceiling sheet was measured to be 0.195Wm-1K-1. This value is about 85% of the value (0.17Wm-1K-1) \) quoted in textbooks. Our pineapple stalk sheet is clearly a poorer heat conductor than the asbestos sheet.  Other parameters determined here – the specific heat capacity, the thermal diffusivity, etc, support our findings that the investigated material can serve as a good material for efficient “cool roof” building desig

An empirical investigation of lead-acid battery desulfation using a high-frequency pulse desulfator

The major cause of deterioration in lead-acid batteries is sulfation. There are patents on the use of high-frequency pulse desulfators to desulfate lead-acid batteries. Also, many products available in the market worldwide claim to use this technique to effectively desulfate lead-acid batteries that deteriorate due to sulfation. But there are little or no systematic studies to evaluate the performance of these products to know whether they do what their manufacturers claim. This research, therefore, aims at empirically evaluating one of such products. Four fully charged 100 Ampere-hour Valve Regulated Lead-Acid Gel batteries were discharged with an electronic-load battery discharger to ascertain their capacities. Thereafter, a high-frequency pulse desulfator was connected to desulfate the battery bank consisting of the four batteries. The battery bank was connected to be charged at the same time by a photovoltaic system. The desulfation experiment lasted for ten weeks but the batteries were tested to know their capacities after two, six, and ten weeks. The results show that the desulfation device works in desulfating lead-acid batteries as there are different degrees of improvement on the capacity of all the batteries. The percentage improvement in the capacity of the batteries is 89.5%, 75.9%, 1.6% and 1.4%, for batteries 1, 2, 3 and 4, respectively

Rejection-free Geometric Cluster Algorithm for Complex Fluids

We present a novel, generally applicable Monte Carlo algorithm for the simulation of fluid systems. Geometric transformations are used to identify clusters of particles in such a manner that every cluster move is accepted, irrespective of the nature of the pair interactions. The rejection-free and non-local nature of the algorithm make it particularly suitable for the efficient simulation of complex fluids with components of widely varying size, such as colloidal mixtures. Compared to conventional simulation algorithms, typical efficiency improvements amount to several orders of magnitude