An Overlay Architecture for Personalized Object Access and Sharing in a Peer-to-Peer Environment

Due to its exponential growth and decentralized nature, the Internet has evolved into a chaotic repository, making it difficult for users to discover and access resources of interest to them. As a result, users have to deal with the problem of information overload. The Semantic Web's emergence provides Internet users with the ability to associate explicit, self-described semantics with resources. This ability will facilitate in turn the development of ontology-based resource discovery tools to help users retrieve information in an efficient manner. However, it is widely believed that the Semantic Web of the future will be a complex web of smaller ontologies, mostly created by various groups of web users who share a similar interest, referred to as a Community of Interest. This thesis proposes a solution to the information overload problem using a user driven framework, referred to as a Personalized Web, that allows individual users to organize themselves into Communities of Interests based on ontologies agreed upon by all community members. Within this framework, users can define and augment their personalized views of the Internet by associating specific properties and attributes to resources and defining constraint-functions and rules that govern the interpretation of the semantics associated with the resources. Such views can then be used to capture the user's interests and integrate these views into a user-defined Personalized Web. As a proof of concept, a Personalized Web architecture that employs ontology-based semantics and a structured Peer-to-Peer overlay network to provide a foundation of semantically-based resource indexing and advertising is developed. In order to investigate mechanisms that support the resource advertising and retrieval of the Personalized Web architecture, three agent-driven advertising and retrieval schemes, the Aggressive scheme, the Crawler-based scheme, and the Minimum-Cover-Rule scheme, were implemented and evaluated in both stable and churn environments. In addition to the development of a Personalized Web architecture that deals with typical web resources, this thesis used a case study to explore the potential of the Personalized Web architecture to support future web service workflow applications. The results of this investigation demonstrated that the architecture can support the automation of service discovery, negotiation, and invocation, allowing service consumers to actualize a personalized web service workflow. Further investigation will be required to improve the performance of the automation and allow it to be performed in a secure and robust manner. In order to support the next generation Internet, further exploration will be needed for the development of a Personalized Web that includes ubiquitous and pervasive resources

Preparation, structure and properties of gold-based ‘ruby’ sodium silicate glass: A model metal-glass nano-composite

Gold ruby glass has been well-known for its deep red color dating back to Roman times but the role of gold nano-particles (AuNPs) in the creation of color was revealed only in 20th century. Glass alchemists discovered early on that addition of tin promotes the development of color. However, the underlying mechanism, which relies on the availability of electrons for oxidation/reduction and growth of AuNP above a minimum size, remains unclear. Additionally, very little information is available on how the electrical properties of such glasses are affected by the presence of gold nanoparticles or tin doping. In this dissertation, a gold-doped sodium trisilicate glass has been investigated as a model for metal-glass nano-composite in order to unravel the origin of the optical, electrical, and thermal properties of ruby glass in terms of atomistic structure and microstructure. This study also provides an insight on the dynamics of electrons in silicate glasses.We investigated the development of the AuNPs by extended X-ray absorption fine structure (EXAFS), in situ X-ray absorption near edge structure (XANES) analysis, and optical spectroscopy of sodium trisilicate glass doped with ≤ 0.1mol% of gold (as HAuCl4) and varying amounts of SnO 2 (0.005-0.1 mol%). The samples were prepared by the conventional melt-quench technique followed by thermal treatment. XANES was measured at the Au L3 -edge and Sn K-edge while heating the glass up to 550 °C. Development of the ruby color was followed concurrently with in situ optical spectroscopy; the in situ spectroscopy showed a red-shift and a blue-shift of the surface plasmon resonance peak due to AuNPs forming in samples with varying concentration of SnO2 with heat treatment. The XANES and EXAFS indicated transformation of ionic gold to metallic gold, and conversion from Au-O to Au-Au bonds. SnO2 doped samples had lower metallic gold i.e. Au-Au bonds in the as-quenched state, but also had a shorter incubation time and a faster growth of AuNPs during the heat treatment process. The tin remained as Sn4+ ions in the distorted octahedral site surrounded by mainly oxygen throughout i.e. both before and after the heat treatment. The addition of SnO2 helped gold dissolve in the glass matrix during melting, while acting as a nucleating agent at lower temperatures.Based on above results, a new model for the formation of AuNPs controlled by electron (FACE) availability is presented. The model suggests that the electrons involved in the reduction process through Au+1 + e-  Au0 control the growth process and in tin-free glass they mainly come from NBO. To prove this concept, additional electrons were generated by X-ray irradiation. The results showed a faster growth of AuNPs by the availability of these additional electrons, confirming that the reduction of gold ions is the rate limiting process that required availability of electrons. In addition, the X-ray irradiation produced the ruby color more effectively if the sample was irradiated during heating instead of before heating as the irradiation created new defects. However, the effect of the reduction process from X-irradiation diminished when higher SnO2 was present in the glasses. After the reduction stage, the growth of AuNPs, Au0 + Au0  AuNP, was controlled by the diffusion of gold atoms and Ostwald ripening of particles.The major factors that determine the influence of SnO2 on the AuNP formation include: i) Au+1 is more uniformly distributed in glass matrix of the as-quenched sample than in the tin-free sample, ii) the electrons associated with SnO_6^(2-) unit are more mobile than those associated with the NBOs of silicate network, and iii) SnO2 lowers the surface energy as a surfactant so that AuNPs may grow at a faster rate. The experimental results are in excellent qualitative agreement with the proposed FACE model.From scanning transmission electron microscope observations, spherical and non-spherical AuNPs were found in the glass matrix after annealing. In general, the average size of gold nanoparticles increased with heat treatment, as expected from the growth process. A smaller size and narrower size distribution of AuNPs were observed in the sample with higher SnO2 concentration. Different orientations (i.e. multiple grains) were found in several AuNPs, possibly originating from the coalescence of two particles. Some AuNPs appeared to have a core-shell structure but the energy dispersive X-ray spectroscopy did not show higher Sn, Na or Cl concentration in or surrounding the AuNPs.The Open Z-scan technique showed nonlinearity which demonstrated an optical limiting behavior. The samples with higher gold amounts showed a higher nonlinear absorption coefficient (β). The addition of tin to the samples caused the deep ruby red color within the glass but there was a lower β in these samples. Moreover, the tin-doped samples showed a negative or a positive β depending on the intensity of laser. Finally, the addition of both 0.1 mol% gold and 0.1 mol% tin increased the DC electrical conductivity, which originated from the sodium ion transport, as compared to the undoped base glass. The activation energy of DC conductivity decreased when the amount of tin increased with the gold content kept constant. The Na+ ion transport appeared to be different for the two types of dopings: Au doping caused general expansion of molar volume whereas tin doping enhanced the polarizability of the medium

Heterogeneous Catalysis Transesterification of Waste Cooking Oil (WCO) and Parametric Optimization

Waste cooking oil (WCO) is considered to be a potential feedstock for biodiesel due to its low cost, availability in avoiding the food-for-fuel competition of the same oil resources, and also associated with WCO disposal. Hence, the WCO was chosen for this study to investigate the transesterification reaction of microwave energy pretreated WCO using heterogeneous catalyst derived from chicken bones from the calcination temperature of 900 °C (C900). WCO and catalyst characterization were performed. Two models; alkali heterogeneous catalysis transesterification and microwave energy pretreated alkali heterogeneous catalysis transesterification, were designed of 62 experiments to investigate the effect of five reaction variables; Methanol to oil molar ratio, catalyst concentration, reaction temperature, reaction time and microwave heating time. The interaction effects of reaction variables were studied using statistical tool of Central Composite Design (CCD) technique of Response Surface Methodology (RSM). It is found that reaction temperature and reaction time are the significant variables for heterogeneous catalysis transesterification whereas reaction time, microwave heating time and C900 concentration were dominant variables to the FAME yield. The optimum FAME yield of microwave energy pretreated transesterification was at 91.94 % and qualitatively higher than that of alkali heterogeneous catalysis transesterification which gained 98.308 %. The FAME yield conditions proved that microwave energy can improve the transesterification and enhance the product yield up to 3.38 times higher than alkali heterogeneous catalysis transesterification within a shorter length of tim

Exploring the Relationship of Teachers’ Attitudes, Perceptions, and Knowledge towards Integrated STEM

The purpose of this study was to investigate the relationship between teachers’ attitudes, perceptions, and knowledge towards integrated STEM. The participants in this study were 185 Indonesian Pre-service and In-service teachers from the eastern, western, and central regions of Indonesia with the difference in ethnicity and culture. The exploration of these three domains was based on the demographic data, teachers’ attributes, and their contribution to the educational system. An adopted and adapted STEM questionnaire was administered online which comprises the likert-scale items that were used as the research tool. The result showed that teachers have a positive correlation between the attitude and knowledge towards integrated STEM, especially for sustainability the quality of education in Indonesia. The implication of this research was about the possibility of elaborating more on the domain of components or sub-components related to current problems faced by teachers towards integrated STEM that exposes teachers’ behavior as the priority for teaching assessment

Biomonitoring of Mercury Contamination at Petroleum Production Platforms in the Gulf of Thailand using Transplanted Green Mussel, Perna viridis

Assessment of mercury contamination was conducted using transplanted green mussels (Perna viridis). Mussels were first exposed to HgCl2 at 0.5, 1.0, 2.5, and 5.0 nmol/L for 8 weeks at laboratory conditions. The result showed that Hg level in the water decreased rapidly, while Hg in mussels increased coincidentally with the applied doses. After 8 weeks the Hg, levels in tissue were a thousand-fold higher than that in the water. Mussels were then transplanted to 3 petroleum production platforms for field study. The result revealed that survival and growth rates of transplanted mussels at all 3 stations were in close to each other but significantly lower than that from the reference site. Hg concentrations in the tissues of transplanted mussels ranged from less than 0.010 to 0.173 µg/g, and Hg concentrations in mussel tissues from all stations were significantly increased within 2 months, while Hg levels in mussel tissues from reference site were not changed. Hg levels of transplanted mussels increased with increasing depths of the water. The transplanted mussels showed no signs of any physical anomalies, indicating that transplanted mussels could be maintained for up to 3 months in an un-natural habitat, such as petroleum production platforms, where food is much less abundant

Composites from recycled polypropylene and rubberwood flour: Effects of composition on mechanical properties

The mechanical properties of composites from recycled waste plastic and waste sawdust are of interest in trying to convert these waste streams to useful products. The development of these composites from natural fiber is therefore receiving widespread attention due to the growing environmental awareness. The effects of compositions were investigated including different grades of plastic (virgin and recycled) and amounts of wood flour, coupling agent, and ultraviolet (UV) stabilizer on mechanical and physical properties of polypropylene/rubberwood flour (RWF)composites. Virgin polypropylene gave better mechanical properties than recycled (recycled polypropylene (rPP)), both in composites and as unfilled plastic. RWF content exceeding 25 wt% enhanced the strength of RWF-reinforced rPP composites. The modulus and hardness of composites increased linearly with wood flour loadings. Maleic anhydride-grafted polypropylene (MAPP) as a coupling agent increased the strength, modulus, and hardness of the composites. However, addition of 1 wt% UV stabilizer degraded the mechanical properties. Therefore, 4 wt% MAPP content is recommended to achieve good mechanical properties of rPP/RWF composites, while the amount of UV stabilizer should be as small as possible to avoid its negative influence.the graduate school of Prince of Songkla University, the Government budget Fund, Rubberwood Technology and Management Research Grou

Optimizing the formulation of polypropylene and rubberwood flour composites for moisture resistance by mixture design

D-optimal mixture experimental design was used to determine the optimal mixture of composites from rubberwood Hevea brasiliensis) flour and recycled polypropylene and to systematically analyze the effects of composition, namely recycled polypropylene, rubberwood flour, maleic anhydride-grafted polypropylene, and ultraviolet stabilizer fractions. Panel samples were extruded, and their properties were characterized. The overall compositions significantly affected water absorption, thickness swelling, flexural strength and modulus, and maximum strain. Water absorption and thickness swelling increased with the fraction of rubberwood flour. At long immersion times, flexural strength and modulus decreased, but maximum strain increased with high fraction of rubberwood flour. The fraction of maleic anhydridegrafted polypropylene only slightly affected water absorption and flexural properties, while the ultraviolet stabilizer fraction had a clear negative effect increasing water absorption and decreasing flexural properties. The models fitted were used for optimization of a desirability score, substituting for the multiple objectives modeled. The optimal formulation found was 68.9 wt% recycled polypropylene, 25.0 wt% rubberwood flour, 5.0 wt% maleic anhydride-grafted polypropylene, 0.1 wt% ultraviolet stabilizer, and 1.0 wt% lubricant. This formulation of the composites can be used for most suitable applications based on the moisture resistance

Application of a quality function deployment technique to design and develop furniture products

It is important for furniture manufacturers to develop an effective organization, produce high-quality products, and develop new product designs which correlate with customer requirements to obtain more satisfactory output. Quality function deployment (QFD) was employed to design and produce new types of prototype plywood wardrobe. Customer product requirements were transformed into House of Quality of QFD. These require applied techniques to design the new forms of the product through changes in, for example, product shape, pattern, color, functionality, and quality of materials used. Product satisfaction was evaluated by customers composing of groups of product users and sales agent stores. The results revealed that the average satisfaction value of the new prototype increased from 2.71 to 4.08 points over the current products (an increase of about 54.87%). Hypothesis testing of customer satisfaction between the current and the new designs was found to significantly increase with regard to the QFD approach

Minimizing the creep of recycled polypropylene/rubberwood flour composites with mixture design experiments

Composites of rubberwood flour (RWF) and recycled polypropylene (rPP) were produced into panel samples by using a twin-screw extruder. The effects on creep behavior of mixture fractions of rPP, RWF, maleic anhydride-grafted polypropylene (MAPP), and ultraviolet (UV) stabilizer were studied in a D-optimal mixture design. Creep was significantly affected by the composition. Increasing the fraction of RWF decreased creep, while MAPP and UV stabilizer increased it. The models fitted were used to optimize a desirability score that balanced multiple creep characteristics. The modelbased optimal formulation 50.5 wt% rPP, 44.9 wt% RWF, 3.5 wt% MAPP, 0.1 wt% UV stabilizer, and 1.0 wt% lubricant was experimentally validated to have low creep closely matching the model predictions.The authors gratefully acknowledge the financial support from the graduate school of Prince of Songkla University,the Government budget Fund (Research Grant Code: 2555A11502062), and Rubberwood Technology and Management Research Group (ENG-54-27-11-0137-S) of Faculty of Engineering, Prince of Songkla University, Thailand

The optimal formulation of recycled polypropylene/rubberwood flour composites from experiments with mixture design

A mixture design was used in experiments, to determine the optimal mixture for composites of rubberwood flour (RWF) and reinforced recycled polypropylene (rPP). The mixed materials were extruded into panels. Effects were determined of the mixture components rPP, RWF, maleic anhydride-grafted polypropylene (MAPP), and ultraviolet (UV) stabilizer, on the mechanical properties. The overall composition significantly affected flexural, compressive, and tensile properties. The fractions of recycled polypropylene and rubberwood flour increased all the mechanical material properties; however, increasing one fraction must be balanced by decreasing the other, and the rubberwood flour fraction had a higher effect size. The fraction of MAPP was best kept in mid-range of the fractions tested, while the UV stabilizer fraction overall degraded the mechanical properties. Our results suggest that the fraction of UV stabilizer should be as small as possible to minimize its negative influences. The models fitted were used for optimization of a desirability score, substituting for the multiple objectives modeled. The optimal formulation found was 50.3 wt% rPP, 44.5 wt% RWF, 3.9 wt% MAPP, 0.2 wt% UV stabilizer, and 1.0 wt% lubricant; the composite made with this formulation had good mechanical properties that closely matched the model predictions.Prince of Songkla Graduate Studies Grant, the Government budget Fund (Research Grant Code: 2555A11502062)and Rubberwood Technology and Management Research Group (ENG-54-27-11-0137-S) of Faculty of Engineering,Prince of Songkla Universit