Elemental analysis of wood materials by external millibeam thick target PIXE

PIXE (Particle Induce X-ray Emission spectrometry) was used for analysing stem bark and stem wood of Scots pine, Norway spruce and Silver birch. Thick samples were irradiated, in laboratory atmosphere, with 3 MeV protons and the beam current was measured indirectly using a photo multiplicator (PM) tube. Both point scans and bulk analyses were performed with the 1 mm diameter proton beam. In bulk analyses, whole bark and sectors of discs of the stem wood were dry ashed at 550 ˚C. The ashes were homogenised by shaking and prepared to target pellets for PIXE analyses. This procedure generated representative samples to be analysed, but the enrichment also enabled quantification of some additional trace elements. The ash contents obtained as a product of the sample preparation procedure also showed to be of great importance in the evaluation of results in environmental studies. Spot scans from the pith of pine wood outwards, showed clearly highest concentrations of manganese, calcium and zinc in the first spot irradiated, or 2-3 times higher than in the surrounding wood. For stem wood from the crown part of a pine this higher concentration level was found in the first four spots/mms, including the pith and the two following growth rings. Zinc showed increasing concentrations outwards in sapwood of the pine stem, with the over-all lowest concentrations in the inner half of the sapwood. This could indicate emigration of this element from sapwood being under transformation to heartwood. Point scans across sapwood of pine and spruce showed more distinct variations in concentrations relative to hearth wood. Higher concentrations of e.g. zinc, calcium and manganese were found in earlywood than in denser latewood. Very high concentrations of iron and copper were also seen for some earlywood increments. The ash content of stem bark is up to and order higher than for the stem wood. However, when the elemental concentration in ashes of bark and wood of the same disc were compared, these are very similar – this when trees are growing at spots with no anthropogenic contamination from the atmosphere. The largest difference was obtained for calcium which appeared at two times high concentrations in ashes of bark than in ashes of the wood (ratio of 2). Pine bark is often used in monitoring of atmospheric pollution, where concentrations in bark samples are compared. Here an alternative approach is suggested: Bark and the underlying stem wood of a pine trees are dry ashed and analysed. The elemental concentration in the bark ash is then compared to the concentration of the same element in the wood ash. Comparing bark to wood includes a normalisation for the varying availability of an element from the soil at different sites. When this comparison is done for the ashes of the materials, a normalisation is also obtained for the general and locally different enrichment of inorganic elements from wood to bark. Already a ratio >2 between the concentration in the bark ash and the concentration in the wood ash could indicate atmospheric pollution. For monitoring where bark is used, this way of “inwards” comparison is suggested - instead of comparing to results from analyses of bark from other trees (read reference areas), growing at sites with different soil and, locally, different climate conditions. This approach also enables evaluation of atmospheric pollution from sampling of only relative few individual trees –preferable during forest felling.

Bonding of Composite Resin to Alumina and Zirconia Ceramics with Special Emphasis on Surface Conditioning and Use of Coupling Agents

Dental oxide ceramics have been inspired by their biocompability and mechanical properties which have made durable all-ceramic structures possible. Clinical longevity of the prosthetic structures is dependent on effective bonding with luting cements. As the initial shear bond strength values can be comparable with several materials and procedures, long-term durability is affected by ageing. Aims of the current study were: to measure the shear bond strength of resin composite-to-ceramics and to evaluate the longevity of the bond; to analyze factors affecting the bond, with special emphasis on: the form of silicatization of the ceramic surface; form of silanization; type of resin primer and the effect of the type of the resin composite luting cement; the effect of ageing in water was studied regarding its effect to the endurance of the bond. Ceramic substrates were alumina and yttrium stabilized zirconia. Ceramic conditioning methods included tribochemical silicatization and use of two silane couplings agents. A commercial silane primer was used as a control silane. Various combinations of conditioning methods, primers and resin cements were tested. Bond strengths were measured by shear bond strength method. The longevity of the bond was generally studied by thermocycling the materials in water. Additionally, in one of the studies thermal cycling was compared with long-term water storaging. Results were analysed statistically with ANOVA and Weibull analysis. Tribochemical treatment utilizing air pressure of 150 kPa resulted shear bond strengths of 11.2 MPa to 18.4 MPa and air pressure of 450 kPa 18.2 MPa to 30.5 MPa, respectively. Thermocycling of 8000 cycles or four years water storaging both decreased shear bond strength values to a range of 3.8 MPa to 7.2 MPa whereas initial situation varied from 16.8. Mpa to 23.0 MPa. The silane used in studies had no statistical significance. The use of primers without 10-MDP resulted spontaneous debonding during thermocycling or shear bond strengths below 5 MPa. As conclusion, the results showed superior long-term bonding with primers containing 10-MDP. Silicatization with silanizing showed improved initial shear bond strength values which considerably decreased with ageing in water. Thermal cycling and water storing for up to four years played the major role in reduction of bond strength, which could be due to thermal fatigue of the bonding interface and hydrolytic degradation of the silane coupled interface.

Characterization and treatment of sisal fiber residues for cement-based composite application

Sisal fiber is an important agricultural product used in the manufacture of ropes, rugs and also as a reinforcement of polymeric or cement-based composites. However, during the fiber production process a large amount of residues is generated which currently have a low potential for commercial use. The aim of this study is to characterize the agricultural residues by the production and improvement of sisal fiber, called field bush and refugo and verify the potentiality of their use in the reinforcement of cement-based composites. The residues were treated with wet-dry cycles and evaluated using tensile testing of fibers, scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Compatibility with the cement-based matrix was evaluated through the fiber pull-out test and flexural test in composites reinforced with 2 % of sisal residues. The results indicate that the use of treated residue allows the production of composites with good mechanical properties that are superior to the traditional composites reinforced with natural sisal fibers.

Repair of segmental bone defects with fiber-reinforced composite: a study of material development and an animal model on rabbits

The Repair of segmental defects in load-bearing long bones is a challenging task because of the diversity of the load affecting the area; axial, bending, shearing and torsional forces all come together to test the stability/integrity of the bone. The natural biomechanical requirements for bone restorative materials include strength to withstand heavy loads, and adaptivity to conform into a biological environment without disturbing or damaging it. Fiber-reinforced composite (FRC) materials have shown promise, as metals and ceramics have been too rigid, and polymers alone are lacking in strength which is needed for restoration. The versatility of the fiber-reinforced composites also allows tailoring of the composite to meet the multitude of bone properties in the skeleton. The attachment and incorporation of a bone substitute to bone has been advanced by different surface modification methods. Most often this is achieved by the creation of surface texture, which allows bone growth, onto the substitute, creating a mechanical interlocking. Another method is to alter the chemical properties of the surface to create bonding with the bone – for example with a hydroxyapatite (HA) or a bioactive glass (BG) coating. A novel fiber-reinforced composite implant material with a porous surface was developed for bone substitution purposes in load-bearing applications. The material’s biomechanical properties were tailored with unidirectional fiber reinforcement to match the strength of cortical bone. To advance bone growth onto the material, an optimal surface porosity was created by a dissolution process, and an addition of bioactive glass to the material was explored. The effects of dissolution and orientation of the fiber reinforcement were also evaluated for bone-bonding purposes. The Biological response to the implant material was evaluated in a cell culture study to assure the safety of the materials combined. To test the material’s properties in a clinical setting, an animal model was used. A critical-size bone defect in a rabbit’s tibia was used to test the material in a load-bearing application, with short- and long-term follow-up, and a histological evaluation of the incorporation to the host bone. The biomechanical results of the study showed that the material is durable and the tailoring of the properties can be reproduced reliably. The Biological response - ex vivo - to the created surface structure favours the attachment and growth of bone cells, with the additional benefit of bioactive glass appearing on the surface. No toxic reactions to possible agents leaching from the material could be detected in the cell culture study when compared to a nontoxic control material. The mechanical interlocking was enhanced - as expected - with the porosity, whereas the reinforcing fibers protruding from the surface of the implant gave additional strength when tested in a bone-bonding model. Animal experiments verified that the material is capable of withstanding load-bearing conditions in prolonged use without breaking of the material or creating stress shielding effects to the host bone. A Histological examination verified the enhanced incorporation to host bone with an abundance of bone growth onto and over the material. This was achieved with minimal tissue reactions to a foreign body. An FRC implant with surface porosity displays potential in the field of reconstructive surgery, especially regarding large bone defects with high demands on strength and shape retention in load-bearing areas or flat bones such as facial / cranial bones. The benefits of modifying the strength of the material and adjusting the surface properties with fiber reinforcement and bone-bonding additives to meet the requirements of different bone qualities are still to be fully discovered.

The energy efficiency of chilled beam systems in an office building at different climates

Besides the sustaining of healthy and comfortable indoor climate, the air conditioning system should also achieve for energy efficiency. The target indoor climate can be ob-tained with different systems; this study focuses on comparing the energy efficiency of different air conditioning room unit systems in different climates. The calculations are made with dynamic energy simulation software IDA ICE by comparing the indoor cli-mate and energy consumption of an office building with different systems in different climates. The aim of the study is to compare the energy efficiency of chilled beam systems to other common systems: variable air volume, fan coil and radiant ceiling systems. Besides the annual energy consumption also the sustainability of target indoor climate is compared between the simulations. Another aim is to provide conclusions to be used in the product development of the chilled beam systems’ energy efficiency. The adaptable chilled beam system and the radiant ceiling system prove to be energy efficient independent of the climate. The challenge of reliable comparison is that other systems are not able to reach the target indoor climate as well as the others. The complex calculation environment of the simulation software, made assumptions and excluding of the financial aspects complicate comparing the big picture. The results show that the development of the chilled beam systems should concentrate on energy efficient night heating, flexible demand based ventilation and capacity control and possibilities on integrating the best practices with other systems. 

Characterisation of Laser Beam and Paper Material Interaction

It is known already from 1970´s that laser beam is suitable for processing paper materials. In this thesis, term paper materials mean all wood-fibre based materials, like dried pulp, copy paper, newspaper, cardboard, corrugated board, tissue paper etc. Accordingly, laser processing in this thesis means all laser treatments resulting material removal, like cutting, partial cutting, marking, creasing, perforation etc. that can be used to process paper materials. Laser technology provides many advantages for processing of paper materials: non-contact method, freedom of processing geometry, reliable technology for non-stop production etc. Especially packaging industry is very promising area for laser processing applications. However, there are only few industrial laser processing applications worldwide even in beginning of 2010´s. One reason for small-scale use of lasers in paper material manufacturing is that there is a shortage of published research and scientific articles. Another problem, restraining the use of laser for processing of paper materials, is colouration of paper material i.e. the yellowish and/or greyish colour of cut edge appearing during cutting or after cutting. These are the main reasons for selecting the topic of this thesis to concern characterization of interaction of laser beam and paper materials. This study was carried out in Laboratory of Laser Processing at Lappeenranta University of Technology (Finland). Laser equipment used in this study was TRUMPF TLF 2700 carbon dioxide laser that produces a beam with wavelength of 10.6 μm with power range of 190-2500 W (laser power on work piece). Study of laser beam and paper material interaction was carried out by treating dried kraft pulp (grammage of 67 g m-2) with different laser power levels, focal plane postion settings and interaction times. Interaction between laser beam and dried kraft pulp was detected with different monitoring devices, i.e. spectrometer, pyrometer and active illumination imaging system. This way it was possible to create an input and output parameter diagram and to study the effects of input and output parameters in this thesis. When interaction phenomena are understood also process development can be carried out and even new innovations developed. Fulfilling the lack of information on interaction phenomena can assist in the way of lasers for wider use of technology in paper making and converting industry. It was concluded in this thesis that interaction of laser beam and paper material has two mechanisms that are dependent on focal plane position range. Assumed interaction mechanism B appears in range of average focal plane position of 3.4 mm and 2.4 mm and assumed interaction mechanism A in range of average focal plane position of 0.4 mm and -0.6 mm both in used experimental set up. Focal plane position 1.4 mm represents midzone of these two mechanisms. Holes during laser beam and paper material interaction are formed gradually: first small hole is formed to interaction area in the centre of laser beam cross-section and after that, as function of interaction time, hole expands, until interaction between laser beam and dried kraft pulp is ended. By the image analysis it can be seen that in beginning of laser beam and dried kraft pulp material interaction small holes off very good quality are formed. It is obvious that black colour and heat affected zone appear as function of interaction time. This reveals that there still are different interaction phases within interaction mechanisms A and B. These interaction phases appear as function of time and also as function of peak intensity of laser beam. Limit peak intensity is the value that divides interaction mechanism A and B from one-phase interaction into dual-phase interaction. So all peak intensity values under limit peak intensity belong to MAOM (interaction mechanism A one-phase mode) or to MBOM (interaction mechanism B onephase mode) and values over that belong to MADM (interaction mechanism A dual-phase mode) or to MBDM (interaction mechanism B dual-phase mode). Decomposition process of cellulose is evolution of hydrocarbons when temperature is between 380- 500°C. This means that long cellulose molecule is split into smaller volatile hydrocarbons in this temperature range. As temperature increases, decomposition process of cellulose molecule changes. In range of 700-900°C, cellulose molecule is mainly decomposed into H2 gas; this is why this range is called evolution of hydrogen. Interaction in this range starts (as in range of MAOM and MBOM), when a small good quality hole is formed. This is due to “direct evaporation” of pulp via decomposition process of evolution of hydrogen. And this can be seen can be seen in spectrometer as high intensity peak of yellow light (in range of 588-589 nm) which refers to temperature of ~1750ºC. Pyrometer does not detect this high intensity peak since it is not able to detect physical phase change from solid kraft pulp to gaseous compounds. As interaction time between laser beam and dried kraft pulp continues, hypothesis is that three auto ignition processes occurs. Auto ignition of substance is the lowest temperature in which it will spontaneously ignite in a normal atmosphere without an external source of ignition, such as a flame or spark. Three auto ignition processes appears in range of MADM and MBDM, namely: 1. temperature of auto ignition of hydrogen atom (H2) is 500ºC, 2. temperature of auto ignition of carbon monoxide molecule (CO) is 609ºC and 3. temperature of auto ignition of carbon atom (C) is 700ºC. These three auto ignition processes leads to formation of plasma plume which has strong emission of radiation in range of visible light. Formation of this plasma plume can be seen as increase of intensity in wavelength range of ~475-652 nm. Pyrometer shows maximum temperature just after this ignition. This plasma plume is assumed to scatter laser beam so that it interacts with larger area of dried kraft pulp than what is actual area of beam cross-section. This assumed scattering reduces also peak intensity. So result shows that assumably scattered light with low peak intensity is interacting with large area of hole edges and due to low peak intensity this interaction happens in low temperature. So interaction between laser beam and dried kraft pulp turns from evolution of hydrogen to evolution of hydrocarbons. This leads to black colour of hole edges.

Capacity of an I-beam made of S960 QC based on Eurocode 3

The capacity of beams is a very important factor in the study of durability of structures and structural members. The capacity of a high-strength steel I-beam made of S960 QC was investigated in this study. The investigation included assessment of the service limits and ultimate limits of the steel beam. The thesis was done according to European standards for steel structures, Eurocode 3. An analytical method was used to determine the throat thickness, deformation, elastic and plastic moment capacities as well as the fatigue life of the beam. The results of the analytical method were compared with those obtained by Finite Element Analysis (FEA). Elastic moment capacity obtained by the analytical method was 172 kNm. FEA and the analytical method predicted the maximum lateral-torsional buckling (LTB) capacity in the range of 90-93 kNm and the probability of failure as a result of LTB is estimated to be 50%. The lateral buckling capacity meant that the I-beam can carry a safe load of 300 kN instead of the initial load of 600 kN. The beam is liable to fail shortly after exceeding the elastic moment capacity. Based on results in of the different approaches, it was noted that FEA predicted higher deformation values on the load-deformation curve than the analytical results. However, both FEA and the analytical methods predicted identical results for nominal stress range and moment capacities. Fatigue life was estimated to be in the range of 53000-64000 cycles for bending stress range using crack propagation equation and strength-life approach. As Eurocode 3 is limited to steel grades up to S690, results for S960 must be verified with experimental data and appropriate design rules.

Development of porous glass-fiber reinforced composite for bone implants. Evaluation of antimicrobial effect and implant fixation

Cranial bone reconstructions are necessary for correcting large skull bone defects due to trauma, tumors, infections and craniotomies. Traditional synthetic implant materials include solid or mesh titanium, various plastics and ceramics. Recently, biostable glass-fiber reinforced composites (FRC), which are based on bifunctional methacrylate resin, were introduced as novel implant solution. FRCs were originally developed and clinically used in dental applications. As a result of further in vitro and in vivo testing, these composites were also approved for clinical use in cranial surgery. To date, reconstructions of large bone defects were performed in 35 patients. This thesis is dedicated to the development of a novel FRC-based implant for cranial reconstructions. The proposed multi-component implant consists of three main parts: (i) porous FRC structure; (ii) bioactive glass granules embedded between FRC layers and (iii) a silver-polysaccharide nanocomposite coating. The porosity of the FRC structure should allow bone ingrowth. Bioactive glass as an osteopromotive material is expected to stimulate the formation of new bone. The polysaccharide coating is expected to prevent bacterial colonization of the implant. The FRC implants developed in this study are based on the porous network of randomly-oriented E-glass fibers bound together by non-resorbable photopolymerizable methacrylate resin. These structures had a total porosity of 10–70 volume %, of which > 70% were open pores. The pore sizes > 100 μm were in the biologically-relevant range (50-400 μm), which is essential for vascularization and bone ingrowth. Bone ingrowth into these structures was simulated by imbedding of porous FRC specimens in gypsum. Results of push-out tests indicated the increase in the shear strength and fracture toughness of the interface with the increase in the total porosity of FRC specimens. The osteopromotive effect of bioactive glass is based on its dissolution in the physiological environment. Here, calcium and phosphate ions, released from the glass, precipitated on the glass surface and its proximity (the FRC) and formed bone-like apatite. The biomineralization of the FRC structure, due to the bioactive glass reactions, was studied in Simulated Body Fluid (SBF) in static and dynamic conditions. An antimicrobial, non-cytotoxic polysaccharide coating, containing silver nanoparticles, was obtained through strong electrostatic interactions with the surface of FRC. In in vitro conditions the lactose-modified chitosan (chitlac) coating showed no signs of degradation within seven days of exposure to lysozyme or one day to hydrogen peroxide (H2O2). The antimicrobial efficacy of the coating was tested against Staphylococcus aureus and Pseudomonas aeruginosa. The contact-active coating had an excellent short time antimicrobial effect. The coating neither affected the initial adhesion of microorganisms to the implant surface nor the biofilm formation after 24 h and 72 h of incubation. Silver ions released to the aqueous environment led to a reduction of bacterial growth in the culture medium.

Chaos and Unpredictability in the Vibration of an Elasto-Plastic Beam

This contribution discusses the nonlinear dynamics of a pin-ended elasto-plastic beam with both kinematic and isotropic hardening. An iterative numerical procedure based on the operator split technique is developed in order to deal with the nonlinearities in the equations of motion. Free and forced responses for harmonic sinusoidal and square wave excitations are investigated. Numerical simulations present many interesting behaviors such as jump phenomena, sensitivity to initial conditions, chaos and transient chaos. These results indicate that there are practical problems in predicting the response of the beam even when periodic steady state response is expected.

Experimental Vibration Characteristics of a Beam with Nonlinear Support Using Receptance Coupling Analysis

This paper applies the Multi-Harmonic Nonlinear Receptance Coupling Approach (MUHANORCA) (Ferreira 1998) to evaluate the frequency response characteristics of a beam which is clamped at one end and supported at the other end by a nonlinear cubic stiffness joint. In order to apply the substructure coupling technique, the problem was characterised by coupling a clamped linear beam with a nonlinear cubic stiffness joint. The experimental results were obtained by a sinusoidal excitation with a special force control algorithm where the level of the fundamental force is kept constant and the level of the harmonics is kept zero for all the frequencies measured.

Composite artistry in the Book of Numbers : a study in biblical narrative conventions

The present thesis discusses the coherence or lack of coherence in the book of Numbers, with special regard to its narrative features. The fragmented nature of Numbers is a well-known problem in research on the book, affecting how we approach and interpret it, but to date there has not been any thorough investigation of the narrative features of the work and how they might contribute to the coherence or the lack of coherence in the book. The discussion is pursued in light of narrative theory, and especially in connection to three parameters that are typically understood to be invoked in the interpretation of narratives: 1) a narrative paradigm, or ‘story,’ meaning events related to each other temporally, causally, and thematically, in a plot with a beginning, middle, and end; 2) discourse, being the expression plane of a narrative, or the devices that an author has at hand in constructing a narrative; 3) the situation or languagegame of the narrative, prototypical examples being factual reports, which seeks to depict a state of affairs, and storytelling narratives, driven by a demand for tellability. In view of these parameters the present thesis argues that it is reasonable to form four groups to describe the narrative material of Numbers: genuine narratives (e.g. Num 12), independent narrative sequences (e.g. Num 5:1-4), instrumental scenes and situations (e.g. Num 27:1-5), and narrative fragments (e.g. Num 18:1). These groups are mixed throughout with non-narrative materials. Seen together, however, the narrative features of these groups can be understood to create an attenuated narrative sequence from beginning to end in Numbers, where one thing happens after another. This sequence, termed the ‘larger story’ of Numbers, concerns the wandering of Israel from Sinai to Moab. Furthermore, the larger story has a fragmented plot. The end-point is fixed on the promised land, Israel prepares for the wandering towards it (Num 1-10), rebels against wandering and the promise and is sent back into the wilderness (Num 13-14), returns again after forty years (Num 21ff.), and prepares for conquering the land (Num 22-36). Finally, themes of the promised land, generational succession, and obedience-disobedience, operate in this larger story. Purity is also a significant theme in the book, albeit not connected to plot in the larger story. All in all, sequence, plot, and theme in the larger story of Numbers can be understood to bring some coherence to the book. However, neither aspect entirely subsumes the whole book, and the four groups of narrative materials can also be understood to underscore the incoherence of the work in differentiating its variegated narrative contents. Numbers should therefore be described as an anthology of different materials that are loosely connected through its narrative features in the larger story, with the aim of informing Israelite identity by depicting a certain period in the early history of the people.

Unidirectional fiber-reinforced composite as an oral implant abutment material: Experimental studies of E-glass fiber/BisGMA-TEGDMA polymer in vitro

Fiber-reinforced composites (FRCs) are a new group of non-metallic biomaterials showing a growing popularity in many dental and medical applications. As an oral implant material, FRC is biocompatible in bone tissue environment. Soft tissue integration to FRC polymer material is unclear. This series of in vitro studies aimed at evaluating unidirectional E-glass FRC polymer in terms of mechanical, chemical, and biological properties in an attempt to develop a new non-metallic oral implant abutment alternative. Two different types of substrates were investigated: (a) Plain polymer (BisGMA 50%–TEGDMA 50%) and (b) Unidirectional FRC. The mechanical behavior of high fiber-density FRCs was assessed using a three-point bending test. Surface characterization was performed using scanning electron and spinning disk confocal microscopes. The surface wettability/energy was determined using sessile drop method. The blood response, including blood-clotting ability and platelet morphology was evaluated. Human gingival fibroblast cell responses - adhesion kinetics, adhesion strength, and proliferation activity - were studied in cell culture environment using routine test conditions. A novel tissue culture method was developed and used to evaluate porcine gingival tissue graft attachment and growth on the experimental composite implants. The analysis of the mechanical properties showed that there is a direct proportionality in the relationship between E-glass fiber volume fraction and toughness, modulus of elasticity, and load bearing capacity; however, flexural strength did not show significant improvement when high fiber-density FRC is used. FRCs showed moderate hydrophilic properties owing to the presence of exposed glass fibers on the polymer surface. Blood-clotting time was shorter on FRC substrates than on plain polymer. The FRC substrates also showed higher platelet activation state than plain polymer substrates. Fibroblast cell adhesion strength and proliferation rate were highly pronounced on FRCs. A tissue culture study revealed that gingival epithelium and connective tissue established an immediate close contact with both plain polymer and FRC implants. However, FRC seemed to guide epithelial migration outwards from the tissue/implant interface. Due to the anisotropic and hydrophilic nature of FRC, it can be concluded that this material enhances biological events related with soft tissue integration on oral implant surface.

Design and validation of stateful composite RESTful web services

A web service is a software system that provides a machine-processable interface to the other machines over the network using different Internet protocols. They are being increasingly used in the industry in order to automate different tasks and offer services to a wider audience. The REST architectural style aims at producing scalable and extensible web services using technologies that play well with the existing tools and infrastructure of the web. It provides a uniform set of operation that can be used to invoke a CRUD interface (create, retrieve, update and delete) of a web service. The stateless behavior of the service interface requires that every request to a resource is independent of the previous ones facilitating scalability. Automated systems, e.g., hotel reservation systems, provide advanced scenarios for stateful services that require a certain sequence of requests that must be followed in order to fulfill the service goals. Designing and developing such services for advanced scenarios with REST constraints require rigorous approaches that are capable of creating web services that can be trusted for their behavior. Systems that can be trusted for their behavior can be termed as dependable systems. This thesis presents an integrated design, analysis and validation approach that facilitates the service developer to create dependable and stateful REST web services. The main contribution of this thesis is that we provide a novel model-driven methodology to design behavioral REST web service interfaces and their compositions. The behavioral interfaces provide information on what methods can be invoked on a service and the pre- and post-conditions of these methods. The methodology uses Unified Modeling Language (UML), as the modeling language, which has a wide user base and has mature tools that are continuously evolving. We have used UML class diagram and UML state machine diagram with additional design constraints to provide resource and behavioral models, respectively, for designing REST web service interfaces. These service design models serve as a specification document and the information presented in them have manifold applications. The service design models also contain information about the time and domain requirements of the service that can help in requirement traceability which is an important part of our approach. Requirement traceability helps in capturing faults in the design models and other elements of software development environment by tracing back and forth the unfulfilled requirements of the service. The information about service actors is also included in the design models which is required for authenticating the service requests by authorized actors since not all types of users have access to all the resources. In addition, following our design approach, the service developer can ensure that the designed web service interfaces will be REST compliant. The second contribution of this thesis is consistency analysis of the behavioral REST interfaces. To overcome the inconsistency problem and design errors in our service models, we have used semantic technologies. The REST interfaces are represented in web ontology language, OWL2, that can be part of the semantic web. These interfaces are used with OWL 2 reasoners to check unsatisfiable concepts which result in implementations that fail. This work is fully automated thanks to the implemented translation tool and the existing OWL 2 reasoners. The third contribution of this thesis is the verification and validation of REST web services. We have used model checking techniques with UPPAAL model checker for this purpose. The timed automata of UML based service design models are generated with our transformation tool that are verified for their basic characteristics like deadlock freedom, liveness, reachability and safety. The implementation of a web service is tested using a black-box testing approach. Test cases are generated from the UPPAAL timed automata and using the online testing tool, UPPAAL TRON, the service implementation is validated at runtime against its specifications. Requirement traceability is also addressed in our validation approach with which we can see what service goals are met and trace back the unfulfilled service goals to detect the faults in the design models. A final contribution of the thesis is an implementation of behavioral REST interfaces and service monitors from the service design models. The partial code generation tool creates code skeletons of REST web services with method pre and post-conditions. The preconditions of methods constrain the user to invoke the stateful REST service under the right conditions and the post condition constraint the service developer to implement the right functionality. The details of the methods can be manually inserted by the developer as required. We do not target complete automation because we focus only on the interface aspects of the web service. The applicability of the approach is demonstrated with a pedagogical example of a hotel room booking service and a relatively complex worked example of holiday booking service taken from the industrial context. The former example presents a simple explanation of the approach and the later worked example shows how stateful and timed web services offering complex scenarios and involving other web services can be constructed using our approach.

Predicting variety composite means without diallel crossing

Prediction of variety composite means was shown to be feasible without diallel crossing the parental varieties. Thus, the predicted mean for a quantitative trait of a composite is given by: Yk = a1 sigmaVj + a2sigmaTj + a3 - a4, with coefficients a1 = (n - 2k)/k²(n - 2); a2 = 2n(k - 1)/k²(n - 2); a3 = n(k - 1)/k(n - 1)(n - 2); and a4 = n²(k - 1)/k(n - 1)(n - 2); summation is for j = 1 to k, where k is the size of the composite (number of parental varieties of a particular composite) and n is the total number of parent varieties. Vj is the mean of varieties and Tj is the mean of topcrosses (pool of varieties as tester), and and are the respective average values in the whole set. Yield data from a 7 x 7 variety diallel cross were used for the variety means and for the "simulated" topcross means to illustrate the proposed procedure. The proposed prediction procedure was as effective as the prediction based on Yk = - ( -)/k, where and refer to the mean of hybrids (F1) and parental varieties, respectively, in a variety diallel cross. It was also shown in the analysis of variance that the total sum of squares due to treatments (varieties and topcrosses) can be orthogonally partitioned following the reduced model Yjj’ = mu + ½(v j + v j’) + + h j+ h j’, thus making possible an F test for varieties, average heterosis and variety heterosis. Least square estimates of these effects are also given

Portfolio Selection via Composite Measure Analysis: Evidence from the U.S. Stock Market

The aim of this research is to examine the pricing anomalies existing in the U.S. market during 1986 to 2011. The sample of stocks is divided into decile portfolios based on seven individual valuation ratios (E/P, B/P, S/P, EBIT/EV, EVITDA/EV, D/P, and CE/P) and price momentum to investigate the efficiency of individual valuation ratio and their combinations as portfolio formation criteria. This is the first time in financial literature when CE/P is employed as a constituent of composite value measure. The combinations are based on median scaled composite value measures and TOPSIS method. During the sample period value portfolios significantly outperform both the market portfolio and comparable glamour portfolios. The results show the highest return for the value portfolio that was based on the combination of S/P & CE/P ratios. The outcome of this research will increase the understanding on the suitability of different methodologies for portfolio selection. It will help managers to take advantage of the results of different methodologies in order to gain returns above the market.