FTIR and thermodynamic study of Pakistani and international crude oils in 1,4-dioxane

This paper is the continuation of our previous paper, which concerned the viscosity of crude oils in 1,4-dioxane. In this paper, we present the Fourier Transform Infrared (FTIR) spectroscopy and thermodynamic study of Pakistani and International crude oils. Degree of branching, chain length, and degree of substitution in aromatic by FTIR data were calculated. Thermodynamic parameters viz., energy of activation (E_η), free energy change of activation (ΔG^*), latent heat of vaporization (L_v), and entropy change of activation (ΔS^*) have also been evaluated.     

Modeling of fouling layer deposition in cross-flow microfiltration during tomato juice clarification

The effect of parameters, such as transmembrane pressure and axial flow rate, on membrane fouling during tomato juice clarification were studied by cross-flow microfiltration using flat sheet polyvinylidenefluoride membranes. The effect of fouling on permeate flux was modeled using a classical constant pressure dead-end filtration equation and its modified form for cross-flow filtration. The main physico-chemical properties of tomato juice were evaluated. The clarified juice was very similar to the feed except for insoluble solids and lycopene, which were concentrated in the retentate. Cake formation was identified as the main reason for flux decline. At different axial flow rates, the fouling mechanism evolves from cake filtration to an intermediate pore blocking mechanism with increasing pressure.     

CFD simulation of acoustic cavitation in a crude oil upgrading sonoreactor and prediction of collapse temperature and pressure of a cavitation bubble

In acoustic cavitation, high pressure and temperature are generated due to cavitation bubble collapse in the liquid bulk around the bubble which causes physical and chemical changes in the liquid. In this study, pressure distribution in water caused by ultrasonic wave propagation in a sonoreactor was investigated. Active cavitation zones were determined by calculating acoustic pressure threshold for cavitation inception and compared with experimental results. Collapse pressure and temperature were predicted 3000 atm and 3200 K, respectively, for crude oil at temperature of 25 °C by evaluating cavitation bubble dynamics in the exerted acoustic field. As a consequence, the huge amounts of energy generated by this phenomenon can be applied for changes in oil properties and crude oil upgrading.     

A study of crystalline biomaterials for articular cartilage bioengineering

This study examines the suitability of marine origin coral species, Porites lutea (POR) and the hydrozoan Millepora dichotoma (MIL), for use as novel three dimensional growth matrices in the field of articular cartilage tissue engineering. Therefore, mesenchymal stem cells (MSCs) and chondrocytes were grown on the skeletal material obtained from each of these two organisms to investigate their potential use as three dimensional scaffolding for cartilage tissue growth. Chondrogenic induction of MSCs was achieved by addition of transforming growth factor-β1 (TGF-β1) and insulin growth factor-I (IGF-I). Cell adherence, proliferation, differentiation and tissue development were investigated through six weeks of culture. Cartilage tissue growth and chondrocytic phenotype maintenance of each cell type were examined by cell morphology, histochemical analyses, expression of collagen type II and quantitative measures of glycosaminoglycan (GAG) content. The MSCs and the chondrocytes were shown good adherence to the scaffolds and maintenance of the chondrocytic phenotype in the initial stages of culture. However after two weeks of culture on MIL and three weeks on POR these cultures began to exhibit signs of further differentiation and phenotypic loss. The shown results indicated that POR was a better substrate for chondrocytes phenotype maintenance than MIL. We believe that surface modification of POR combined with mechanical stimuli will provide a suitable environment for chondrogenic phenotype maintenance. Further investigation of POR and other novel coralline biomatrices is indicated and warranted in the field of cartilage tissue engineering applications.     

The effect of urethral introducer tip catheters on the incidence of urinary tract infection outcomes in spinal cord injured patients

PURPOSE: We attempted to determine whether an introducer tip catheter reduces urinary tract infection in spinal cord injured patients on intermittent catheterization. MATERIALS AND METHODS: The introducer tip catheter bypasses the colonized 1.5 cm. of the distal urethra. Enrolled patients were prospectively entered into the study in alternate groups depending on whether they reflex voided: group 1--on intermittent catheterization with the introducer tip catheter but not voiding spontaneously or wearing an external urinary catheter, group 2--same as group 1 but using a nonintroducer tip catheter; group 3--on intermittent catheterization with the introducer tip catheter, voiding by reflex and wearing an external urinary catheter, and group 4--same as group 3 but using a nonintroducer tip catheter. RESULTS: Statistical significance was shown when comparing patients using versus not using the introducer tip catheter regardless of whether an external urinary catheter was worn (p = 0.0121). A greater difference was noted between patients using and not using the introducer tip catheter in the intermittent catheterization only group (p = 0.0093). CONCLUSIONS: The introducer tip catheter decreased urinary tract infections in hospitalized men with spinal cord injury on intermittent catheterization.     

Structural,optical and magnetic properties of the Fe2TiO5 nanopowders

Iron titanate nanopowders with a particle size range of 48–70?nm could be obtained after calcinations of the dried gel at 900°C for 2?h. Fe₂TiO₅ indicates a ferrimagnetic–paramagnetic behaviour, as evidenced by using vibrating sample magnetometer at room temperature. In the temperature range of 25–300°C the empirical equation of the heat capacity C _p (J/mol?K)?=??692.328?+?1.39?T?+?3.757?×?10⁷/T ² for Fe₂TiO₅ was determined from differential scanning calorimetry. Direct optical band gap of Fe₂TiO₅ was calculated using the Tauc model by UV-Vis diffuse reflectance spectroscopy. Band gap energy of Fe₂TiO₅ was determined as 1.95?eV.     

The Effect of a Porous Layer on I-V Characterization of a Polysilicon p-n Junction

In this study, we investigate the effect of an etching process on the rectification property of a p-n junction. To achieve this goal, electrochemical etching (ECE) was employed, using a HF based solution. The morphological properties of the porous samples were characterized by Field Emission Scanning Electron Microscopy (FESEM). The images showed distributed pores in the range of several nanometers. Also, the distribution showed improvement in the size of meso- to macropores. The Current-Voltage measurement of porous and pristine poly silicon p-n junctions was done in dark and illumination conditions. I-V properties in illumination revealed intensive rectification in the proposed junction. Under dark condition, the ideality factor of the porous poly silicon p-n junction was approximately 3.9, which compared to 4.2 for the pristine sample demonstrates 7% improvement. Also, the light sensitivity was increased in the porous one. Furthermore, the light response (Δφ _BP) of the porous sample gave the value of 0.02. In conclusion, the rectification mode could be enhanced through relevant porosity.     

Finite element model updating using bees algorithm

In this paper the application of bees algorithm (BA) in the finite element (FE) model updating of structures is investigated. BA is an optimization algorithm inspired by the natural foraging behavior of honeybees to find food sources. The weighted sum of the squared error between the measured and computed modal parameters is used as the objective function. To demonstrate the effectiveness of the proposed method, BA is applied on a piping system to update several physical parameters of its FE model. To this end, the modal parameters of the numerical model are compared with the experimental ones obtained through modal testing. Moreover, to verify the performance of BA, it is compared with the genetic algorithm, the particle swarm optimization and the inverse eigensensitivity method. Comparison of the results indicates that BA is a simple and robust approach that could be effectively applied to the FE model updating problems.     

Evolution of Emergency Management in Malaysia

Various types of disaster ranging from biological, structural collapse, fire and explosion, landslides and meteorological incidents have struck Malaysia. Safety and emergency laws and regulations in Malaysia had evolved in pace with the development and industrialisation of the country. Some of these disasters were land‐marked disasters whereby various safety and emergency acts and regulations were amended or introduced. In this article, the history of the evolution of various Safety and Emergency Laws, Regulations and Acts in the country since independence in 1957 until the establishment of the Permanent Guidelines for Disaster Management and Relief Operations in 1997 is presented. Lessons from past disasters and the rapid expansion of industrialisation have greatly influenced the evolution of safety and emergency management in Malaysia. However, this intermediary phase in the pursuit of development is often accompanied by an increase in vulnerability (McEntire, 1997). This paper discusses reasons that are attributed to the increase in vulnerability as well as the challenges faced by the nation in the area of safety and emergency planning.