Abstract: The variation in the microstructure in terms of free volume and the thermal properties, such as specific heat(C_p), glass transition temperature(T_g) of 8 MeV electron irradiated Polystyrene (PS) at different doses have been measured using Positron Annihilation Lifetime Spectroscopy (PALS) and Differential Scanning Calorimetry (DSC) respectively. PALS results showed that at irradiation dose 75 KGy the free volume of the polymer matrix decreases suggesting cross liking of the inter chain and structure appears to be stabilized. In the DSC measurements the specific heat at constant pressure suggests the scission of chains at 100 KGy which is well reflected in the increase of the free volume at this dosage. The observed changes in T_g are not prominent and do not really reflect the changes in free volume upon irradiation.

Abstract: Cush-cush yam (Dioscorea trifida), is a sub-utilized tropical crop, rich in starch, which grown in tropical areas. The exploitation of its starch has great potential. The objectives of this research was to modify starch isolated from dark-cush-cush yam, which grown in the Venezuelan Amazonian, and commercial cassava starch, by cross linking, in order to characterize and compare them with their native counterparts. The results showed that differences in the amylose content affected the composition, structure and functional properties of both starches. The degree of substitution (DS) was more significant in the cush-cush starch yam than that of the cassava starch, even if both were within the ranges allowed by the FDA. The granular size of cassava starch was slightly changed by modification. The rheological properties also changed, increasing the viscosity peak, breakdown, consistency and setback. Finally, that modification method conferred great stability to the starches gelatinization.

Abstract: High – temperature superconductors are required in many fields of modern technology. However the difficulties related to creation of low temperature conditions for superconductors and the labor-intensive production and operation are hinder their widespread application. After analyzing the possible causative mechanism of dreams, I surmised that in order to signals from the information field penetrating through the sleeper’s eyes into a brain during the rapid eye movement sleep, axoplasm of neurons must possess a high conductivity. I then inferred that this high conductivity was due to the effect of the cranial bones. These bones apparently protect the brain not only from physical injuries but also from various kinds of wave “noise”; this noise produces oscillating motions of positive ions in the axoplasm of neurons, and, as a result, electrical resistance is increased. I measured the electrical resistance of a number of metallic conductors, which I coated with materials of various compositions and found that when nichrome wires were covered with clean bone glue, there was a conspicuous decrease in this resistance; in conductors containing iron, covered with clean bone glue, the resistance decreased to zero. If a thin layer of bone glue is covered with Moment rubber glue, the coating of ardent superconductor becomes elastic that makes the superconductor shockproof and resistant to moisture and magnetic fields and thus promising for modern engineering.

Abstract: Analysis of physicochemical properties of Eucalyptus citriodora gum revealed that the gum is mildly acidic, brownish in colour, ionic and has the potentials to swell four times its original volume. GCMS analysis of the gum indicated the presence of some carboxylic acids, pyran-4-one, 1,3-dioxolane, benzofuran and 1,2-ethanediyl acetate while analysis of its FTIR spectrum revealed functional groups that are common to polysaccharides. Scanning electron micrograph of the gum also revealed the existence of particle aggregations with some internal bridges within the system. Rheological properties of the gum were found to be affected by pH, concentration, temperature and by the presence of some electrolytes (KCl, CaCl₂, AlCl₃ and urea). Average value of intrinsic viscosity deduced from Huggins and Kraemer plots was 3.51 dL/g while the sum of their constants was 0.36 (i,e< 0.5 and suggested the absence of molecular association). Calculated value of the Power law constant was (b= 0.812) less than unity and pointed to a rod like conformation. From the Master’s curve, the existence of dilute and concentrated regimes, (corresponding to η_sp0α C^1.04 (at C> C*) and η_sp0 α C^0.95 (at C < C*) respectively) was established. Eucalyptus citriodora gum is a shear thinning, non-Newtonian polymer that is characterized by pseudoplastic behavior. The gum has some potentials for use as food additives and for other industrial applications.

Abstract: The variation of specific heat (C_p) of natural rubber (NR) is studied by Differential Scanning Calorimetry (DSC). The NR samples are filled with different fillers (nanoclay, TiO₂, and nanosilica) at different concentrations. The DSC measurements are done in N₂ atmosphere with constant pressure of 0.3 bar to prevent any oxidation of the samples. The temperature has been varied up to 210°C from -40°C at a constant heating rate of 10°C \min throughout the experiment and Proteus analysis software is used to study the variation of specific heat (C_p) as function of both temperature and filler concentrations. The investigation shows that the Cp values increase with the increase of filler concentrations. Due to nanometer range diameter, these fillers fill up some of the free volume holes of NR sample. The fillers also make cross-link with NR chains causing an increase the molecular weight of NR as well as the C_p values. Thus the fillers act as active fillers for NR sample.