Showing papers by "Applied Science Private University published in 2002"

Chemical modification of hemp, sisal, jute, and kapok fibers by alkalization

Abstract: Plant fibers are rich in cellulose and they are a cheap, easily renewable source of fibers with the potential for polymer reinforcement. The presence of surface impurities and the large amount of hydroxyl groups make plant fibers less attractive for reinforcement of polymeric materials. Hemp, sisal, jute, and kapok fibers were subjected to alkalization by using sodium hydroxide. The thermal characteristics, crystallinity index, reactivity, and surface morphology of untreated and chemically modified fibers have been studied using differential scanning calorimetry (DSC), X-ray diffraction (WAXRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), respectively. Following alkalization the DSC showed a rapid degradation of the cellulose between 0.8 and 8% NaOH, beyond which degradation was found to be marginal. There was a marginal drop in the crystallinity index of hemp fiber while sisal, jute, and kapok fibers showed a slight increase in crystallinity at caustic soda concentration of 0.8–30%. FTIR showed that kapok fiber was found to be the most reactive followed by jute, sisal, and then hemp fiber. SEM showed a relatively smooth surface for all the untreated fibers; however, after alkalization, all the fibers showed uneven surfaces. These results show that alkalization modifies plant fibers promoting the development of fiber–resin adhesion, which then will result in increased interfacial energy and, hence, improvement in the mechanical and thermal stability of the composites. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2222–2234, 2002

Density Functional Study of Benzene Adsorption on Pt(111)

Abstract: The adsorption of benzene on Pt(111) was analyzed using first-principles density functional theoretical cluster and periodic slab calculations. The preferred adsorption site at low coverage is the bridge(30) site with an adsorption energy of 117 kJ/mol. At the bridge(30) site, two of the C pz orbitals are well aligned for overlap with the metal dz2 and dyz orbitals, leading to a strong C−Pt bond and a strong adsorption energy. The molecule's second important site is the hollow(0) site with an adsorption energy of 75 kJ/mol. Comparing calculated and experimental vibrational frequencies confirms the preference for the bridge site at low coverage and also indicates that adsorption at the hollow(0) site becomes preferred at higher coverage. Adsorption at the hollow(30), the bridge(0) and at the atop sites was found to be unfavorable.

Types of Knowledge and Their Roles in Technology Transfer

Abstract: At the dawn of a new millennium, the most valuable global commodity is knowledge, particularly new knowledge about technology that may give a culture, a company and/or a laboratory an advantage. This paper begins with examples of tacit technology transfer, including atomic weapons technology, whose development suggests that failure to preserve tacit knowledge could lead to uninvention. This discussion is followed by a taxonomy of knowledge, distinguishing between four types--information, skills, judgement and wisdom. These types are used to refine the distinction between tacit and explicit knowledge, including their role in teams.

Greywater Reuse in Urban Agriculture for Poverty Alleviation: A Case Study in Jordan

Abstract: Although Jordan has a human development index higher than most developing countries, about seven percent of its population earns less than the international poverty line of one dollar (US$) a day. Furthermore, because of its scarce water resources and rapidly growing population, the poor, who are increasingly moving to cities, face growing food and water insecurity. This paper describes a pilot project that allowed the poor in Tufileh, Jordan, to reuse untreated household greywater in home gardens. The women of the community used small revolving loans to implement simple greywater recovery systems and set-up gardens. The project allowed the community to offset food purchases and generate income by selling surplus production, saving or earning an average of 10 percent of its income. Had the households used municipal sources for this supplemental irrigation, on average, they would have used 15 percent more water and had 27 percent higher water bills. Moreover, the project helped community members g...

Crack growth resistance in nuclear graphites

Abstract: Crack growth resistance curves for the non-linear fracture parameters KR, JR and R were measured for unirradiated PGA and IM1-24 graphites that are used as moderators in British Magnox and AGR nuclear reactors respectively All the curves show an initial rising part, followed by a plateau region where the measured parameter is independent of crack length JR and R decreased at large crack lengths The initial rising curves were attributed to development of crack bridges in the wake of the crack front, while, in the plateau region, the crack bridging zone and the frontal process zone, ahead of the crack tip, reached steady state values The decreases at large crack lengths were attributed to interaction of the frontal zone with the specimen end face Microscopical evidence for graphite fragments acting as crack bridges showed that they were much smaller than filler particles, indicating that the graphite fragments are broken down during crack propagation There was also evidence for friction points in the crack wake zone and shear cracking of some larger fragments Inspection of KR curves showed that crack bridging contributed ~04 MPa m05 to the fracture toughness of the graphites An analysis of JR and R curves showed that the development of the crack bridging zone in the rising part of the curves contributed ~20% to the total work of fracture Energies absorbed during development of crack bridges and steady state crack propagation were greater for PGA than for IM1-24 graphite These differences reflect the greater extent of irreversible processes occurring during cracking in the coarser microtexture of PGA graphite

Ecophysiology of the Soft Tree Fern, Dicksonia antarctica Labill

Abstract: Environmental constraints on gas exchange, stomatal conductance and water relations were investigated in the Soft Tree Fern, Dicksonia antarctica, at sites across its natural distribution and in the glasshouse. Dicksonia antarctica exhibited strong stomatal response down to a vapour pressure deficit (VPD) of 0.25 kPa, an unusual characteristic when compared with other ground fern species. Net photosynthetic rate may be a response of the microenvironment prevalent during frond development, reflecting acclimatory capacity. Both these ecophysiological characteristics are consistent with the ecological niche of D. antarctica, a long-lived, fire-resistant species that, during its lifetime, may be exposed to: (i) a humid environment beneath a rainforest canopy; and (ii) an exposed environment following wildfire. Maximum net photosynthesis and quantum yield of photosynthesis correlated strongly with VPD and the maximum net photosynthetic rate of 10.8 µmol m−2 s−1 was the highest yet recorded for a fern. These observations are consistent with the relatively low growth typically observed in D. antarctica on sunny, exposed sites and vice versa on cool, humid sites exposed to sunflecks. Favourable water relations maintained under conditions of moderate VPD (2.03 kPa) were probably due to stomatal control. However, inadequate rainfall or high VPD (4.98 kPa) caused water stress, recovery of which was limited by slow water transport through fronds. These observations are consistent with the limitation of D. antarctica distribution to sites sheltered from hot winds and with reliable water supply. The funnel-shaped rosette of fronds of D. antarctica may harvest rainfall and make it accessible to aerial roots situated at the base of fronds. This process may maintain favourable water relations independently of a subterranean root system. This proposed strategy of water acquisition is unique for a fern species and may eliminate a need for soil moisture competition with surrounding plant species. It is suggested that the ecophysiological characteristics observed in D. antarctica in this study may contribute to the ecological niche it occupies, which is characterized by a variable environment.

Tensile properties of heat-treated Nicalon and Hi-Nicalon fibres

Abstract: In this study we compare the tensile properties of two types of Nicalon fibres, one with high oxygen content and the other with low oxygen content. Both types of fibre were coated with a carbon layer during manufacture. The fibres were tested at room temperature in the as-received and desized conditions and after heat treatment at 800 and 1200°C in flowing air and argon. Nicalon-607 and Hi-Nicalon fibres exhibited brittle behaviour and a decrease in tensile strength after heat treatment at 1200°C. It was found that Hi-Nicalon fibres had generally higher tensile properties than Nicalon-607 fibres. It was also observed that the high-oxygen-content fibres had more surface defects than the fibres with low oxygen content.

Fast Fourier Transform and Filtered Image Analyses of Fiber Orientation in OSB

Abstract: The objective of this paper is to investigate the relationship between resolution of images and measurement of fiber orientation in oriented strand board with the ultimate aim of optimising the fiber orientation and quality of the manufactured product. An important consideration has been the capture of images from a distance of 2 meters corresponding to conditions on an OSB production line. In this paper, Filtered Image Analysis (FIA) was used to measure fiber orientation at different resolutions, and results were compared with those for strand grid models. These grid models were adopted to investigate how the FIA technique measures orientation. A two-dimensional Fast Fourier Transform (FFT) analysis was also investigated as a comparative method for measuring fiber orientation. The following conclusions can be drawn: the FFT analysis measures the periodicity of lines and indicates the orientation of lines. The FIA measures the orientation of zones surrounded by lines and shows the orientation of the zones. Hence, the FFT analysis and the FIA analysis measure orientation differently. Both methods are able to measure the fiber orientation of the OSB from a high resolution image. In addition the FIA technique could also measure the fiber orientation from low-resolution images and from a distance of 2 meters. In conclusion, whilst the FFT method is able to analyse high resolution images successfully, the FIA method is superior for analysing low resolution images and the orientation of OSB strands under production condition.

A new class of acyclic nucleoside phosphonates: synthesis and biological activity of 9-[[(phosphonomethyl)aziridin-1-yl]methyl]guanine (PMAMG) and analogues.

Abstract: A new class of acyclic nucleoside phosphonates PMAMG, PMAMA, PMAMC, and PMAMT (compounds 1, 2, 3 and 4) have been synthesized and tested in vitro against a wide variety of viruses, fungi and bacteria. PMAMG (1) was synthesized by the alkylation reaction of acetylguanine with the phosphonate side-chain, diisopropyl [[2-(bromomethyl)aziridin-1-yl]]methylphosphonate (9), followed by deesterification reaction in the presence of TMSBr. In similar way, PMAMA, PMAMC, and PMAMT were prepared.

The effect of corona discharge on Der p 1.

Abstract: Summary Background Reduction of house dust mite allergens in the domestic environment can play an important part in reducing sensitization and in the amelioration of symptoms in atopic individuals Chemical and physical methods have been tried with varied levels of success The present paper presents a novel electrostatic way of destroying Der p 1, the major mite allergen Objective To assess the efficacy of negative Trichel, negative continuous glow, positive pulse and positive continuous glow corona in destroying Der p 1 To determine whether ozone has any effect on the integrity of Der p 1 in the experimental conditions present Methods A simple point-to-plane apparatus was used to irradiate samples of Der p 1 for periods of 1, 15, 30, 45, 60, 120, 180, 240 and 300 min Controls were exposed to the atmosphere with no corona products present for the equivalent time The effect of the corona by-product ozone was investigated alone by exposing samples of Der p 1 to molecular ozone for 60 min Der p 1 concentration was quantified by two-site monoclonal antibody ELISA Results High current negative glow resulted in a 6737% reduction in Der p 1 concentration after 300 min compared with a 505% reduction from a low current Trichel regime High current positive glow corona gave a reduction of 2522% while a low current positive pulse corona caused a 1372% reduction after 300 min All these reductions were statistically significant (P < 005) compared with unexposed controls Negative corona always gave greater percentage reductions in Der p 1 concentration for each time exposure investigated The pattern of percentage reduction follows an exponential rise to maximum relationship in respect to time Samples of Der p 1 were not affected by exposure to molecular ozone Conclusion These data indicate corona products to be a powerful new method of destroying Der p 1 allergen that is not dependent on the presence of the oxidizing corona product ozone

Application of Decision Support System for Sustainable Management of Water Resources in the Azraq Basin—Jordan

Abstract: Water scarcity in Jordan is a significant constraint to development, with limited available water and financial resources. As population and economic activity increase, it will be necessary to implement national strategies that seek to balance the present needs and those of future generations. Multiple variables associated with agricultural crops, industries, and the impact of climate change, were incorporated into a Decision Support System (DSS). The DSS utilized Analytical Hierarchy Process (AHP), which resulted in the prioritization of sustainable water policies for management in the Azraq Basin. The inputs to the DSS were generated through application of Modflow (groundwater), stochastic, and Penman Montieth models and through calculations of water productivity for agricultural and industrial sectors. The results of the DSS make recommendations as to how to enhance long-term sustainability of water resources in Azraq, while allowing for water utilization and economic growth. It is recommended...

Characterisation of biscuit fired bone china body microstructure. Part II: Transmission electron microscopy (TEM) of glassy matrix

Abstract: In this second part of the study, electron transparent specimens of the biscuit fired bone china body were prepared for a conventional transmission electron microscopy (TEM) study. The crystalline phases present in the fired material were noted and particular consideration was given to determination of the nature and composition of the glassy phase. Compositional information on the phases was obtained using energy dispersive X-ray spectrometry (EDS) which was available in conjunction with TEM. Additionally, a simulated glass with a composition typical of that present in the bone china body was prepared and examined by TEM in order to compare its structure and chemistry with that of the glassy phase originally present in the bone china body.

Interactions between an ABS type leadless glaze and a biscuit fired bone china body during glost firing. Part II: investigation of interactions

Abstract: This part of the study involves the investigation of the interactions between an ABS type commercial leadless glaze and a biscuit fired bone china body during glost firing at different temperatures using XRD and SEM techniques. The aim was to obtain detailed and systematic information about the morphological and chemical characteristics of the resultant phases formed at the interfaces. Separate examination of the interactions between the glaze and the experimental crystalline phases of the body prepared earlier, namely anorthite and β-TCP, were also carried out in an effort to show their susceptibility to react with the glaze independently. As a result, the presence of a range of interaction layers with distinctly different morphological and chemical characteristics was successfully demonstrated. It was proposed that β-TCP was the major contributor to the overall interactions by reacting with CaO from the glaze in the presence of water vapour and forming hydroxyapatite crystals at the glaze-body interfaces. Although the exact origin for the development of water vapour in the molten glaze could not determined, several potential sources were suggested.

Monitoring fiber orientation in OSB during production using filtered image analysis

Abstract: The orientation of oriented strand board (OSB) mats has been practically measured on a commercial factory production line to demonstrate the practical capabilities of the filtered image analysis (FIA) technique. Samples have been cut from OSB panels at a range of angles to the panel axis and these samples have been tested in bending. The factory data and the experimental data have been compared in order to investigate the relationship between the practical condition of fiber orientation in the factory and the bending properties as a function of orientation. The following conclusions can be drawn. Fiber orientation in the production line is good and stable irrespective of position across the width of the production line, time of day and changing line speed. The average value for the orientation angle of the forming mat on the production line is approximately 25°. The general shape of the fiber orientation distribution is similar to a normal distribution, however, at the centre of the fiber mat the sharpness of the distribution is greater than a normal distribution. The average orientations of fibers in commercial board lie at 25° and 60° to the longitudinal and perpendicular directions, respectively. The results suggest that there is potential to improve the mean fiber orientation angle of commercial OSB to improve longitudinal values of MOR and MOE, especially where perpendicular properties are not critical.

Interactions between an ABS type leadless glaze and a biscuit fired bone china body during glost firing. Part I: preparation of experimental phases

Abstract: In this paper, part of an extended study, crystalline phases of a biscuit fired bone china body, namely anorthite and beta-tricalcium phosphate (β-TCP), were produced experimentally to be used in subsequent interface studies for simulation of the interactions during glost firing at different temperatures between an ABS type commercial leadless glaze and the individual phases originally present in the body. The research was undertaken based on the premise that bone china has been a product providing the greatest challenge in moving to a totally leadless glaze. High bulk density and low apparent porosity values were achieved from both the anorthite and β-TCP samples through the suitable heat treatments. The microstructural and chemical characteristics of the experimental phases were studied using X-ray diffraction (XRD), scanning (SEM), and transmission (TEM) electron microscopy techniques in combination with EDS analysis. The morphological and chemical similarity of the phases to those originally present in a biscuit fired bone china body was clearly demonstrated. This similarity supports the choice of the experimental material for the interface studies undertaken with these phases in the second part of the study.

Retention of ions in a magnetic chromatograph using high-intensity and high-gradient magnetic fields

Abstract: The control of the retention and separability of samples to be analyzed with high performance liquid chromatography systems is difficult, and usually requires exchanging of the mobile phase and/or the column. We developed a magnetic chromatography (MC) system, which does not require regular exchanging of the mobile phase and/or the column, and uses a continuous-flow system to separate multiple ionic species with different magnetic properties. To demonstrate experimentally the feasibility of such an MC system, we measured the retention of ions in the MC system for aqueous solutions of either pure NaI, CuSO4, NiCl2, CrCl3, or CoCl2. We applied magnetic fields varying from 0 to 3 T to the aqueous solution of transition element cations and anions flowing in an MC system, and demonstrated that the retention time was delayed by about 20 min, and that for Co(II) the chromatogram broadened with increase in the applied magnetic field intensity (H). Furthermore, our results suggest that for ionized transition eleme...

Experimental and Theoretical Studies on Hydrogenation in Multiphase Fixed-Bed Reactors

Abstract: Multiphase fixed-bed reactors have complex hydrodynamic and mass transfer characteristics. The modeling and scale-up are therefore difficult. The present work focuses on the role of mass transfer on the effective reaction rate. The catalytic 1-octene hydrogenation was taken as a model reaction. The reaction rate in the trickle-bed reactor is by a factor of 20 smaller than (theoretically) in the absence of any mass transfer limitations. For high octene concentrations (>10%), the effective reaction rate is limited by the H 2 consumption, above all by the gas/liquid and liquid/solid mass transfer. For lower octene concentrations the reaction is zero order with respect to H 2 and only depends on the octene consumption, i.e., on the interplay of chemical reaction, L/S and intraparticle mass transfer of octene.