Electrical and optical properties of two types of gum Arabic

Gum Arabic is most important commercial poly-saccharine and it is probably the oldest food hydro-colloid in current use. Gum Arabic is naturally obtained from Acacia Senegal and seyal trees which are known to grow in sub Sahara region of the Sudan. Two types of Gum Arabic namely; Acacia Senegal and Seyal were used. X-ray fluorescence [XRF] and Fourier Transformation infrared spectroscopy [FTIR] were used as analytical techniques. The conductivity and dielectric of both types of Gum Arabic were measured as function of frequency. Solutions with different concentration of Gum Arabic for both types were prepared and the Ultraviolet-visible spectroscopy [UV] was used to study the optical properties of these solutions. The XRF results indicated that, Gum Arabic [Acacia Senegal and Seyal] contained Calcium [Ca], Iron [Fe], Copper [Cu], Lead [Pb], and Strontium [Sr]. The FTIR spectra of both types of Gum Arabic showed broad and strong absorption band in the range of 600 to 3000 cm-1. These absorptions were assigned to the different stretching vibrations. The conductivity was found to increase with frequency while the opposite behavior observed for the dielectric. The absorption was found to increase with the increase of concentration

Structure and physical properties of flowering plants of the genus hibiscus

Hibiscus is a genus of flowering plants in the mallow family, Malvacease. It is quite large, containing several hundred species that are native to warm-temperate and have many medical benefits, for example, hibiscus drink lowers high blood pressure. Flowering plants of hibiscus were used in this study. X-ray fluorescence [XRF] and Fourier Transformation infrared spectroscopy [FTIR] were used as analytical techniques. The XRF results indicated that, hibiscus has contained Potassium [K], Calcium [Ca], Iron [Fe], Copper [Cu], Bromine [Br], and Strontium [Sr]. The FTIR spectra of hibiscus showed a broad and strong absorption band in the range1145-2926 cm-1, and these absorptions were assigned to the different stretching vibrations. The conductivity and dielectric properties of hibiscus were measured as function of frequency. The conductivity was found to decrease with frequency while the opposite behavior was observed in case of dielectric. In order to investigate the optical properties, solutions with different concentration of hibiscus were prepared. Ultraviolet-visible spectroscopy [UV] was used to obtain the absorption for different samples with different concentration. The absorption was found to increase with the increase of concentration of hibiscus

Influence of nanosized silica particles on the microstructure lamellar phase of AOT/Isooctane/ Water ternary system

Lamellar phase samples of AOT/isooctane/water ternary system were prepared. The microstructure of the lamellar phase containing nanosized silica particles was examined by optical polarized microscope [OPM] and Small Angle X-ray scattering [SAXS]. Both were used to investigate the phases changing for different silica particle concentrations. The interaction between dopled particle and bilayer of lamellar phase were analyzed and the change of silica concentration shows the defection of the bilayer structure of lamellar phase. The effect of silica concentration was profound in the images of lamellar phase and the phase changed from birefringent to isotropic with increases of concentration

Calculation of the mechanical properties for an amputee hip joint

The theoretical based of real forces exerted on the human hip joints are calculated. Newton's law at condition of equilibrium to forces and torques applied on human hip joints is suggested theoretically and then applied to a case of hip joint injure and prosthetic. It was found that the forces act on the hip joint is nearly two and a half times the weight of the certain person. The lost of weight for the amputee have been taken under account in calculation to improve local manufacturing in Sudan

Calculation of the mechanical properties for lower limb below knee amputee using partial differential equation and finite element method

The theoretical based of real displacement forces exerted on the below knee for an amputee prosthetic are considered. Partial differential equation [PDE] in boundary condition surround of prosthetic is theoretically suggested in order to find forces components and stresses. The theoretical model is applied to simulate the prosthetic. The data of image segmentations are found to support the results obtained using bio-mechanics simulation. Furthermore, it is important to mention that the fitted socket to the underneath knee prosthetic should have a large safe margin with surround of soft tissue

Modelling of fractional relaxation characteristics in wormlike micelles in the presence of a triblock copolymer

Fractional calculus has become an important tool in the analysis of slow relaxation phenomena, such as stress-strain relationships in polymeric materials. The interaction of trilblock copolymer [Pluronics f68] with cetyltrimethylammonium bromide [CTAB]-sodium nitrate [NaNO3] wormlike micellar system in low and high salt concentration is investigated by rheological measurements. Undoped wormlike micellar solution is a viscoelastic fluid which exhibits Maxwellian behavior. Since the rheology of solutions still Maxwellian, a fractional Maxell model is applied to describe any changes. A fractional derivatives of order q and The Maxwell model consists of a spring and dashpot in series. The fractional Maxwell model relating stress to strain is used to fit several experimental results on wormlike micelles in the presence of copolymer. The comparisons between the experimental results and the theoretical predictions are found to be satisfactory

Lyotropic liquid crystalline route for the synthesis of mesoporous silica

Mesoporous silica has been synthesized by gamma-irradiation using a non-ionic surfactant as template in the cubic and hexagonal lyotropic phases. The mesopores obtained in the two phases have different diameters, cubic phase silica being with the smaller pore size of the order of 3-4 nm whereas the hexagonal phase silica is giving large mesopores of value around 15 nm. The wall size differ in the two templated phases as well, cubic phase is with a small thickness of the order of 5.0 nm while the hexagonal silica exhibits a wall thickness of 15 nm under transmission electron microscopy [TEM] approximately. Both these cubic and hexagonal phases were further characterized by small angle X-ray scattering [SAXS], polarizing microscopy and rheometry. Radiation dose and templated phase are both playing effective role in the synthesis of mesoporous silica

Effect of oil types and concentration on ultrasonic measurements of alkyl polyglucosides liquid crystal phases

Phase diagrams for the ternary systems of Glucopone, Water and several hydrocarbons are reported. Four different types of hydrocarbon are used namely; heptane, octane, dodecane and tetradecane. Small angle X-ray scattering [SAXS] and polarizing microscope are used for phase identification and structure characterization. The ternary systems are shown to form different liquid crystalline phases with the Increase of concentration in the following order - cubic, hexagonal, and lamellar. An optical isotropic gel phase with strong elastic properties is found in these systems and Identified as cubic phase. The cubic phase is optically isotropic, transparent and highly viscous phase with three-dimensional structure. The cubic samples showed several diffraction peaks and can be assigned to the la3d space group. The rheological study on the cubic phase is performed. All cubic samples behave as solid-like material with storage modulus G 0.7x10[6] Pa typical of cubic lyotropic materials. The effect of oil concentration in the ultrasonic measurements for the three different liquid crystalline phases is studied. The effect of different types of oil on the ultrasonic measurements is also investigated. The ultrasonic measurements showed that the ultrasonic velocity of the cubic samples Increased as the oil concentrations increased. The ultrasonic measurements showed that the ultrasonic velocities of the lamellar phases decreased with increase in the chain lengths of the hydrocarbon, while the ultrasonic velocities were almost similar for hexagonal phases

Rheological properties of amino-acid based anionic surfactants

The rheological properties of two types of anionic surfactant were investigated. The two surfactants were used, namely Sodium Cocoyl Glutamate [commercially known as Amisoft CS-11] and [commercially known as Amilite GCS-11]. Small angle X-ray scattering [SAXS] and polarizing microscope and used for phase identification and structure characterization. Both surfactants were found to form two-phase region and micellar region. Liquid crystalline phases, for both systems, were found to form at higher surfactant concentration. The rheological investigation indicated that amisoft system showed more solid-like behaviour than that of amilite system. The dynamic viscosity measurement, for the two systems, indicated shear thinning behaviour at low frequency while Newtonian behaviour was found at high frequency range

Rockall score of the acute upper gastrointestinal bleeding patients the experience in Sudan

Innovation of scoring systems helps to rectify personal experience based on subjective evaluation of outcome of patient treatment. To predict the morbidity and mortality in patients presenting with acute upper gastrointestinal bleeding at Ibn-Sina Hospital using the Rockall score. Prospective hospital-based study conducted from June 2007 through December 2007 at the Ibn-Sina Hospital Bleeding Centre. Demographic, data of history and physical examination and results of laboratory investigations of 238 patients were collected and allotted a Rockall score, Child-Pugh class and fed to Statistical Package of Social Sciences [SPSS] to calculate means and find the levels of statistical differences and define the predicted and observed mortality rates. The mean [ +/- SD] age 44.6 [ +/- 15.31] range [8-85] years. There were 190 [79%] males. Patients with oesophageal varices, peptic ulcer, and upper GI tumours were 215 [90.3%], 18 [7.6%], and 5 [2.1%], respectively. The mean/predicted mortality was 3.8% while the actual observed mortality 3.8%. The mortality in cases of oesophageal varices was 8[3.4%], while that of bleeding peptic ulcers was one [0.4%]. Rockall score is feasible, accurate, effective system for predicting outcome in patients with upper GI bleeding. The risk factor for mortality are Rockall score>3, age>70 and rebleeding

Modelling of fractional relaxation behaviour characteristic in polysaccharide systems

Fractional calculus has become an important tool in the analysis of slow relaxation phenomena, such as stress-strain relationships in polymeric materials. The Zener model is an extension of the Maxwell model, which consists of a spring and dashpot in series, with an additional spring in parallel. A fractional rheological description is obtained by replacing the first order time-derivatives in the Maxwell-Zener equation with fractional derivatives of order q and micro. The fractional Zener model relating stress to strain is used to fit several experimental results on polysaccharide. The comparisons between the experimental results and the theoretical predictions are found to be satisfactory

Phase behaviours of amino-acid based anionic surfactants

The phase behaviours of three types of amino-acid based surfactants were explored. They are Sodium Cocoyl Glutamate [commercially known as Amisoft CS-11], Sodium Lauroyl Glutamate [commercially known as Amisoft LS-11] and Sodium Cocoyl Glycinate [commercially known as Amilite GCS-11]. The optical polarized microscope was used to observe the liquid crystalline phases and to capture images. The existence of liquid crystalline phases was further investigated by small angle X-ray scattering. The phase diagrams were investigated as a function of surfactant concentration and as a function of temperature as well. The rheological behaviours of liquid crystalline phase were also investigated. All surfactants were found to form two-phase region, micellar region at low concentration while liquid crystalline phases were found to form at high concentration

Characterization of vesicles of nonionic surfactant mixtures

Nonionic surfactant vesicles are now widely studied as an alternative to liposomes. In the present work, the vesicles were prepared using mixture of nonionic surfactants and the optical microscope with cross polarizers was used in order to observe the vesicles and capture the image. The mixtures of nonionic surfactants Synperonic NP5-dodecyl-beta-D-glycopyranoside [DGP] were prepared for different mol ratio. The critical micelle concentration [CMC] of nonionic surfactant Synperonic NP5 was determined using the tensiometer with Du Nouy ring methods. The effect of different types of salt, namely; KCI, NaCI and CaCl in the CMC was also investigated. The critical vesicle concentration [CVC] for the nonionic mixtures was determined using UV-Visible Spectrophotometer at room temperature. The size of the vesicles of the nonionic mixtures was measured using particle sizer. The CMC and CVC of nonionic vesicles were found to decrease with salt concentration while, the size of the vesicles was found to increase with the salt concentrations. In addition, the rheological behaviours of the nonionic vesicles were investigated. The samples of vesicles showed liquid-like behaviours which were indicated by the domination of the loss modulus, G". The effect of salt concentrations and salt types in the rheological behaviours was also investigated. The dynamic moduli were found to decrease with salt concentration while the effect of the salt types in the elastic and storage moduli was not significant

Influence of different oil types on the rheological behaviour of nonionic oil -in- water microemulsion

Microemulsions were formed at very low oil concentration in the ternary systems. These solutions are optically isotropic with low viscosity. The rheological behaviours of microemulsion of glucopone-water-hydrocarbon systems were investigated. Four different types of hydrocarbon namely heptane, octane, dodecane and tetradecane were considered. The frequency dependent storage and loss modulus were investigated below the critical strain. The critical strain is decreased as the alkane chain lengths increased. The zero shear viscosity was found to increase when longer hydrocarbon chain lengths were considered. However, when surfactant concentrations were further increased, the value of the zero shear viscosity appeared to be going down as the alkane chain length was increased. The discrepancy between the elastic and loss modulus in heptane and octane systems was higher than that corresponds to dodecane and tetradecane systems. The complex viscosity increased as alkane chain lengths of the hydrocarbon increase. In general, the effects of different types of hydrocarbon in the rheological behaviours were found to be more profound in the heptane and octane systems than in the dodecane and tetradecane systems